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Published: 4 June 2021
Last updated: 21 February 2023

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1

Papia, Francesco, Chiara Bellia, and Carina Gabriela Uasuf. "Tropomyosin: A panallergen that causes a worldwide allergic problem." Allergy and Asthma Proceedings 42, no. 5 (September 1, 2021): e145-e151. http://dx.doi.org/10.2500/aap.2021.42.210057.

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Background: Panallergens are proteins that take part in key processes of organisms and, therefore, are ubiquitously distributed with highly conserved sequences and structures. One class of these panallergens is composed of the tropomyosins. The highly heat-stable tropomyosins comprise the major allergens in crustaceans and mollusks, which make them important food allergens in exposed populations. Tropomyosins are responsible for a widespread immunoglobulin E cross-reactivity among allergens from different sources. Allergic tropomyosins are expressed in many species, including parasites and insects. Methods: This panallergen class is divided, according to it capacity of induced allergic symptoms, into allergenic or nonallergenic tropomyosin. Although vertebrate tropomyosins share ∼55% of sequence homology with invertebrate tropomyosins, it has been thought that the invertebrate tropomyosins would not have allergic properties. Nevertheless, in recent years, this opinion has been changed. In particular, tropomyosin has been recognized as a major allergen in many insects. Results: A high grade of homology has been shown among tropomyosins from different species, such as crustaceans and insects, which supports the hypothesis of cross-reactivity among tropomyosins from divergent species. Moreover, the emerging habit of consuming edible insects has drawn the attention of allergists to invertebrate tropomyosin protein due to its potential allergenic risk. Nevertheless, evidence about tropomyosin involvement in clinical allergic response is still scarce and deserves more investigation. Conclusion: This review intended to report allergic reactions associated with different tropomyosins when considering house dust mites, parasites, seafood, and insects, and to summarize our current knowledge about its cross-reactivity because this could help physicians to accurately diagnose patients with food allergy.
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2

Fenderson, P. G., V. A. Fischetti, and M. W. Cunningham. "Tropomyosin shares immunologic epitopes with group A streptococcal M proteins." Journal of Immunology 142, no. 7 (April 1, 1989): 2475–81. http://dx.doi.org/10.4049/jimmunol.142.7.2475.

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Abstract Tropomyosin is an alpha-helical coiled-coil protein with structural similarities to the streptococcal M protein. In order to show serologic cross-reactivity between streptococcal M proteins and tropomyosin, we selected from a panel of murine mAb those which reacted with M proteins and tropomyosins in the ELISA. Western blots were used to study the reactions of each mAb with human and rabbit cardiac and rabbit skeletal tropomyosins. The antibodies were further characterized for their reactions with the additional autoantigens myosin, actin, keratin, and DNA. Five mAb were found which reacted with either PepM5 or ColiM6 protein and tropomyosin in Western blots or ELISA. Two of the tropomyosin positive mAb were also antinuclear antibodies and were inhibited with DNA. In Western blots of cardiac tropomyosins, the mAb reacted with either the 70-kDa dimer of tropomyosin, the 35-kDa monomer, or both. Some differences were observed in the reactions of the mAb with the different tropomyosins in Western blots. The heart cross-reactive epitopes shared between M proteins and tropomyosin were in most instances shared with cardiac myosin. Differences were observed among the reactions of the mAb with the different tropomyosins. This report constitutes the first evidence of serologic cross-reactivity between streptococcal M proteins and tropomyosins.
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3

Gunning, Peter, Geraldine O’neill, and Edna Hardeman. "Tropomyosin-Based Regulation of the Actin Cytoskeleton in Time and Space." Physiological Reviews 88, no. 1 (January 2008): 1–35. http://dx.doi.org/10.1152/physrev.00001.2007.

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Tropomyosins are rodlike coiled coil dimers that form continuous polymers along the major groove of most actin filaments. In striated muscle, tropomyosin regulates the actin-myosin interaction and, hence, contraction of muscle. Tropomyosin also contributes to most, if not all, functions of the actin cytoskeleton, and its role is essential for the viability of a wide range of organisms. The ability of tropomyosin to contribute to the many functions of the actin cytoskeleton is related to the temporal and spatial regulation of expression of tropomyosin isoforms. Qualitative and quantitative changes in tropomyosin isoform expression accompany morphogenesis in a range of cell types. The isoforms are segregated to different intracellular pools of actin filaments and confer different properties to these filaments. Mutations in tropomyosins are directly involved in cardiac and skeletal muscle diseases. Alterations in tropomyosin expression directly contribute to the growth and spread of cancer. The functional specificity of tropomyosins is related to the collaborative interactions of the isoforms with different actin binding proteins such as cofilin, gelsolin, Arp 2/3, myosin, caldesmon, and tropomodulin. It is proposed that local changes in signaling activity may be sufficient to drive the assembly of isoform-specific complexes at different intracellular sites.
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4

Asturias, Juan A., Nuria Gómez-Bayón, M. Carmen Arilla, Alberto Martínez, Ricardo Palacios, Fernando Sánchez-Gascón, and Jorge Martínez. "Molecular Characterization of American Cockroach Tropomyosin (Periplaneta americana Allergen 7), a Cross-Reactive Allergen." Journal of Immunology 162, no. 7 (April 1, 1999): 4342–48. http://dx.doi.org/10.4049/jimmunol.162.7.4342.

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Abstract Inhalation of allergens produced by the American cockroach (Periplaneta americana) induces IgE Ab production and the development of asthma in genetically predisposed individuals. The cloning and expression in Escherichia coli of P. americana tropomyosin allergen have been achieved. The protein shares high homology with other arthropod tropomyosins (80% identity) but less homology with vertebrate ones (50% identity). The recombinant allergen was produced in E. coli as a nonfusion protein with a yield of 9 mg/l of bacterial culture. Both natural and recombinant tropomyosins were purified by isoelectric precipitation. P. americana allergen 1 (Per a 1) and Per a 7 (tropomyosin) are to date the only cross-reacting allergens found in cockroaches. ELISA and Western blot inhibition experiments, using natural and recombinant purified tropomyosins from shrimp and cockroach, showed that tropomyosin induced cross-reactivity of IgE from patients allergic to these allergens, suggesting that this molecule could be a common allergen among invertebrates.
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5

Humayun-Zakaria, Nada, Roland Arnold, Anshita Goel, Douglas Ward, Stuart Savill, and Richard Bryan. "Tropomyosins: Potential Biomarkers for Urothelial Bladder Cancer." International Journal of Molecular Sciences 20, no. 5 (March 4, 2019): 1102. http://dx.doi.org/10.3390/ijms20051102.

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Despite the incidence and prevalence of urothelial bladder cancer (UBC), few advances in treatment and diagnosis have been made in recent years. In this review, we discuss potential biomarker candidates: the tropomyosin family of genes, encoded by four loci in the human genome. The expression of these genes is tissue-specific. Tropomyosins are responsible for diverse cellular roles, most notably based upon their interplay with actin to maintain cellular processes, integrity and structure. Tropomyosins exhibit a large variety of splice forms, and altered isoform expression levels have been associated with cancer, including UBC. Notably, tropomyosin isoforms are detectable in urine, offering the potential for non-invasive diagnosis and risk-stratification. This review collates the basic knowledge on tropomyosin and its isoforms, and discusses their relationships with cancer-related phenomena, most specifically in UBC.
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6

Shafique, Rubaba Hamid, Muhammad Inam, Muhammad Ismail, and Farhana Riaz Chaudhary. "Group 10 Allergens (Tropomyosins) from House-Dust Mites May Cause Covariation of Sensitization to Allergens from Other Invertebrates." Allergy & Rhinology 3, no. 2 (January 2012): ar.2012.3.0036. http://dx.doi.org/10.2500/ar.2012.3.0036.

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Group 10 allergens (tropomyosins) have been assumed to be a major cause of cross-reactivity between house-dust mites (HDMs) and other invertebrates. Despite all of the published data regarding the epidemiology, percent IgE binding and level of sensitization in the population, the role of tropomyosin as a cross-reactive allergen in patients with multiple allergy syndrome still remains to be elucidated. Homology between amino acid sequences reported in allergen databases of selected invertebrate tropomyosins was determined with Der f 10 as the reference allergen. The 66.9 and 54.4% identities were found with selected crustacean and insect species, respectively, whereas only 20.4% identity was seen with mollusks. A similar analysis was performed using reported B-cell IgE-binding epitopes from Met e1 (shrimp allergen) and Bla g7 (cockroach allergen) with other invertebrate tropomyosins. The percent identity in linear sequences was higher than 35% in mites, crustaceans, and cockroaches. The polar and hydrophobic regions in these groups were highly conserved. These findings suggest that tropomyosin may be a major cause of covariation of sensitization between HDMs, crustaceans, and some species of insects and mollusks.
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7

Goins, Lauren M., and R. Dyche Mullins. "A novel tropomyosin isoform functions at the mitotic spindle and Golgi in Drosophila." Molecular Biology of the Cell 26, no. 13 (July 2015): 2491–504. http://dx.doi.org/10.1091/mbc.e14-12-1619.

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Most eukaryotic cells express multiple isoforms of the actin-binding protein tropomyosin that help construct a variety of cytoskeletal networks. Only one nonmuscle tropomyosin (Tm1A) has previously been described in Drosophila, but developmental defects caused by insertion of P-elements near tropomyosin genes imply the existence of additional, nonmuscle isoforms. Using biochemical and molecular genetic approaches, we identified three tropomyosins expressed in Drosophila S2 cells: Tm1A, Tm1J, and Tm2A. The Tm1A isoform localizes to the cell cortex, lamellar actin networks, and the cleavage furrow of dividing cells—always together with myosin-II. Isoforms Tm1J and Tm2A colocalize around the Golgi apparatus with the formin-family protein Diaphanous, and loss of either isoform perturbs cell cycle progression. During mitosis, Tm1J localizes to the mitotic spindle, where it promotes chromosome segregation. Using chimeras, we identified the determinants of tropomyosin localization near the C-terminus. This work 1) identifies and characterizes previously unknown nonmuscle tropomyosins in Drosophila, 2) reveals a function for tropomyosin in the mitotic spindle, and 3) uncovers sequence elements that specify isoform-specific localizations and functions of tropomyosin.
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8

Anthony, D. T., R. J. Jacobs-Cohen, G. Marazzi, and L. L. Rubin. "A molecular defect in virally transformed muscle cells that cannot cluster acetylcholine receptors." Journal of Cell Biology 106, no. 5 (May 1, 1988): 1713–21. http://dx.doi.org/10.1083/jcb.106.5.1713.

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Muscle cells infected at the permissive temperature with temperature-sensitive mutants of Rous sarcoma virus and shifted to the non-permissive temperature form myotubes that are unable to cluster acetylcholine receptors (Anthony, D. T., S. M. Schuetze, and L. L. Rubin. 1984. Proc. Natl. Acad. Sci. USA. 81:2265-2269). Work described in this paper demonstrates that the virally-infected cells are missing a 37-kD peptide which reacts with an anti-tropomyosin antiserum. Using a monoclonal antibody specific for the missing peptide, we show that this tropomyosin is absent from fibroblasts and is distinct from smooth muscle tropomyosins. It is also different from the two previously identified striated muscle myofibrillar tropomyosins (alpha and beta). We suggest that, in normal muscle, this novel, non-myofibrillar, tropomyosin-like molecule is an important component of a cytoskeletal network necessary for cluster formation.
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9

Shanti, K. N., B. M. Martin, S. Nagpal, D. D. Metcalfe, and P. V. Rao. "Identification of tropomyosin as the major shrimp allergen and characterization of its IgE-binding epitopes." Journal of Immunology 151, no. 10 (November 15, 1993): 5354–63. http://dx.doi.org/10.4049/jimmunol.151.10.5354.

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Abstract The major heat-stable shrimp allergen (designated as Sa-II), capable of provoking IgE-mediated immediate type hypersensitivity reactions after the ingestion of cooked shrimp, has been shown to be a 34-kDa heat-stable protein containing 300 amino acid residues. Here, we report that a comparison of amino acid sequences of different peptides generated by proteolysis of Sa-II revealed an 86% homology with tropomyosin from Drosophila melanogaster, suggesting that Sa-II could be the shrimp muscle protein tropomyosin. To establish that Sa-II is indeed tropomyosin, the latter was isolated from uncooked shrimp (Penaeus indicus) and its physicochemical and immunochemical properties were compared with those of Sa-II. Both tropomyosin and Sa-II had the same molecular mass and focused in the isoelectric pH range of 4.8 to 5.4. In the presence of 6 M urea, the mobility of both Sa-II and shrimp tropomyosin shifted to give an apparent molecular mass of 50 kDa, which is a characteristic property of tropomyosins. Shrimp tropomyosin bound to specific IgE antibodies in the sera of shrimp-sensitive patients as assessed by competitive ELISA inhibition and Western blot analysis. Tryptic maps of both Sa-II and tropomyosin as obtained by reverse phase HPLC were superimposable. Dot-blot and competitive ELISA inhibition using sera of shrimp-sensitive patients revealed that antigenic as well as allergenic activities were associated with two peptide fractions. These IgE-binding tryptic peptides were purified and sequenced. Mouse anti-anti-idiotypic antibodies raised against Sa-II specific human idiotypic antibodies recognized not only tropomyosin but also the two allergenic peptides, thus suggesting that these peptides represent the major IgE binding epitopes of tropomyosin. A comparison of the amino acid sequence of shrimp tropomyosin in the region of IgE binding epitopes (residues 50-66 and 153-161) with the corresponding regions of tropomyosins from different vertebrates confirmed lack of allergenic cross-reactivity between tropomyosins from phylogenetically distinct species.
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10

Yamashiro-Matsumura, S., and F. Matsumura. "Characterization of 83-kilodalton nonmuscle caldesmon from cultured rat cells: stimulation of actin binding of nonmuscle tropomyosin and periodic localization along microfilaments like tropomyosin." Journal of Cell Biology 106, no. 6 (June 1, 1988): 1973–83. http://dx.doi.org/10.1083/jcb.106.6.1973.

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Nonmuscle caldesmon purified from cultured rat cells shows a molecular weight of 83,000 on SDS gels, Stokes radius of 60.5 A, and sedimentation coefficient (S20,w) of 3.5 in the presence of reducing agents. These values give a native molecular weight of 87,000 and a frictional ratio of 2.04, suggesting that the molecule is a monomeric, asymmetric protein. In the absence of reducing agents, the protein is self-associated, through disulfide bonds, into oligomers with a molecular weight of 230,000 on SDS gels. These S-S oligomers appear to be responsible for the actin-bundling activity of nonmuscle caldesmon in the absence of reducing agents. Actin binding is saturated at a molar ratio of one 83-kD protein to six actins with an apparent binding constant of 5 X 10(6) M-1. Because of 83-kD nonmuscle caldesmon and tropomyosin are colocalized in stress fibers of cultured cells, we have examined effects of 83-kD protein on the actin binding of cultured cell tropomyosin. Of five isoforms of cultured rat cell tropomyosin, tropomyosin isoforms with high molecular weight values (40,000 and 36,500) show higher affinity to actin than do tropomyosin isoforms with low molecular weight values (32,400 and 32,000) (Matsumura, F., and S. Yamashiro-Matsumura. 1986. J. Biol. Chem. 260:13851-13859). At physiological concentration of KCl (100 mM), 83-kD nonmuscle caldesmon stimulates binding of low molecular weight tropomyosins to actin and increases the apparent binding constant (Ka from 4.4 X 10(5) to 1.5 X 10(6) M-1. In contrast, 83-kD protein has slight stimulation of actin binding of high molecular weight tropomyosins because high molecular weight tropomyosins bind to actin strongly in this condition. As the binding of 83-kD protein to actin is regulated by calcium/calmodulin, 83-kD protein regulates the binding of low molecular weight tropomyosins to actin in a calcium/calmodulin-dependent way. Using monoclonal antibodies to visualize nonmuscle caldesmon along microfilaments or actin filaments reconstituted with purified 83-kD protein, we demonstrate that 83-kD nonmuscle caldesmon is localized periodically along microfilaments or actin filaments with similar periodicity (36 +/- 4 nm) as tropomyosin. These results suggest that 83-kD protein plays an important role in the organization of microfilaments, as well as the control of the motility, through the regulation of the binding of tropomyosin to actin.
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11

Bareja, Ilina, Hugo Wioland, Miro Janco, Philip R. Nicovich, Antoine Jégou, Guillaume Romet-Lemonne, James Walsh, and Till Böcking. "Dynamics of Tpm1.8 domains on actin filaments with single-molecule resolution." Molecular Biology of the Cell 31, no. 22 (October 15, 2020): 2452–62. http://dx.doi.org/10.1091/mbc.e19-10-0586.

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Characterization of the kinetics of Tpm1.8 binding to actin filaments with single-molecule resolution. This work provides molecular insight into actin–tropomyosin filament formation and the role of tropomyosins in regulating actin filament dynamics.
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12

Heeley, D. H., G. K. Dhoot, and S. V. Perry. "Factors determining the subunit composition of tropomyosin in mammalian skeletal muscle." Biochemical Journal 226, no. 2 (March 1, 1985): 461–68. http://dx.doi.org/10.1042/bj2260461.

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Adult rat fast-twitch skeletal muscle such as extensor digitorum longus contains alpha- and beta-tropomyosin subunits, as is the case in the corresponding muscles of rabbit. Adult rat soleus muscle contains beta-, gamma- and delta-tropomyosins, but no significant amounts of alpha-tropomyosin. Evidence for the presence of phosphorylated forms of at least three of the four tropomyosin subunit isoforms was obtained, particularly in developing muscle. Immediately after birth alpha- and beta-tropomyosins were the major components of skeletal muscle, in both fast-twitch and slow-twitch muscles. Differentiation into slow-twitch skeletal muscles was accompanied by a fall in the amount of alpha-tropomyosin subunit and its replacement with gamma- and delta-subunits. After denervation and during regeneration after injury, the tropomyosin composition of slow-twitch skeletal muscle changed to that associated with fast-twitch muscle. Thyroidectomy slowed down the changes in tropomyosin composition resulting from the denervation of soleus muscle. The results suggest that the ‘ground state’ of tropomyosin-gene expression in the skeletal muscle gives rise to alpha- and beta-tropomyosin subunits. Innervation by a ‘slow-twitch’ nerve is essential for the expression of the genes controlling gamma- and delta-subunits. There appears to be reciprocal relationship between expression of the gene controlling the synthesis of alpha-tropomyosin and those controlling the synthesis of gamma- and delta-tropomyosin subunits.
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13

Drees, B., C. Brown, B. G. Barrell, and A. Bretscher. "Tropomyosin is essential in yeast, yet the TPM1 and TPM2 products perform distinct functions." Journal of Cell Biology 128, no. 3 (February 1, 1995): 383–92. http://dx.doi.org/10.1083/jcb.128.3.383.

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Sequence analysis of chromosome IX of Saccharomyces cerevisiae revealed an open reading frame of 166 residues, designated TPM2, having 64.5% sequence identity to TPM1, that encodes the major form of tropomyosin in yeast. Purification and characterization of Tpm2p revealed a protein with the characteristics of a bona fide tropomyosin; it is present in vivo at about one sixth the abundance of Tpm1p. Biochemical and sequence analysis indicates that Tpm2p spans four actin monomers along a filament, whereas Tpmlp spans five. Despite its shorter length, Tpm2p can compete with Tpm1p for binding to F-actin. Over-expression of Tpm2p in vivo alters the axial budding of haploids to a bipolar pattern, and this can be partially suppressed by co-over-expression of Tpm1p. This suggests distinct functions for the two tropomyosins, and indicates that the ratio between them is important for correct morphogenesis. Loss of Tpm2p has no detectable phenotype in otherwise wild type cells, but is lethal in combination with tpm1 delta. Over-expression of Tpm2p does not suppress the growth or cell surface targeting defects associated with tpm1 delta, so the two tropomyosins must perform an essential function, yet are not functionally interchangeable. S. cerevisiae therefore provides a simple system for the study of two tropomyosins having distinct yet overlapping functions.
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14

Lin, J. J., D. M. Helfman, S. H. Hughes, and C. S. Chou. "Tropomyosin isoforms in chicken embryo fibroblasts: purification, characterization, and changes in Rous sarcoma virus-transformed cells." Journal of Cell Biology 100, no. 3 (March 1, 1985): 692–703. http://dx.doi.org/10.1083/jcb.100.3.692.

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Seven polypeptides (a, b, c, 1, 2, 3a, and 3b) have been previously identified as tropomyosin isoforms in chicken embryo fibroblasts (CEF) (Lin, J. J.-C., Matsumura, F., and Yamashiro-Matsumura, S., 1984, J. Cell. Biol., 98:116-127). Spots a and c had identical mobility on two-dimensional gels with the slow-migrating and fast-migrating components, respectively, of chicken gizzard tropomyosin. However, the remaining isoforms of CEF tropomyosin were distinct from chicken skeletal and cardiac tropomyosins on two-dimensional gels. The mixture of CEF tropomyosin has been isolated by the combination of Triton/glycerol extraction of monolayer cells, heat treatment, and ammonium sulfate fractionation. The yield of tropomyosin was estimated to be 1.4% of total CEF proteins. The identical set of tropomyosin isoforms could be found in the antitropomyosin immunoprecipitates after the cell-free translation products of total poly(A)+ RNAs isolated from CEF cells. This suggested that at least seven mRNAs coding for these tropomyosin isoforms existed in the cell. Purified tropomyosins (particularly 1, 2, and 3) showed different actin-binding abilities in the presence of 100 mM KCl and no divalent cation. Under this condition, the binding of tropomyosin 3 (3a + 3b) to actin filaments was significantly weaker than that of tropomyosin 1 or 2. CEF tropomyosin 1, and probably 3, could be cross-linked to form homodimers by treatment with 5,5'-dithiobis-(2-nitrobenzoate), whereas tropomyosin a and c formed a heterodimer. These dimer species may reflect the in vivo assembly of tropomyosin isoforms, since dimer formation occurred not only with purified tropomyosin but also with microfilament-associated tropomyosin. The expression of these tropomyosin isoforms in Rous sarcoma virus-transformed CEF cells has also been investigated. In agreement with the previous report by Hendricks and Weintraub (Proc. Natl. Acad. Sci. USA., 78:5633-5637), we found that major tropomyosin 1 was greatly reduced in transformed cells. We have also found that the relative amounts of tropomyosin 3a and 3b were increased in both the total cell lysate and the microfilament fraction of transformed cells. Because of the different actin-binding properties observed for CEF tropomyosins, changes in the expression of these isoforms may, in part, be responsible for the reduction of actin cables and the alteration of cell shape found in transformed cells.
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15

Jeong, Kyoung Yong, Jongweon Lee, In-Yong Lee, Han-Il Ree, Chein-Soo Hong, and Tai-Soon Yong. "Analysis of Amino Acid Sequence Variations and Immunoglobulin E-Binding Epitopes of German Cockroach Tropomyosin." Clinical Diagnostic Laboratory Immunology 11, no. 5 (September 2004): 874–78. http://dx.doi.org/10.1128/cdli.11.5.874-878.2004.

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ABSTRACT The allergenicities of tropomyosins from different organisms have been reported to vary. The cDNA encoding German cockroach tropomyosin (Bla g 7) was isolated, expressed, and characterized previously. In the present study, the amino acid sequence variations in German cockroach tropomyosin were analyzed in order to investigate its influence on allergenicity. We also undertook the identification of immunodominant peptides containing immunoglobulin E (IgE) epitopes which may facilitate the development of diagnostic and immunotherapeutic strategies based on the recombinant proteins. Two-dimensional gel electrophoresis and immunoblot analysis with mouse anti-recombinant German cockroach tropomyosin serum was performed to investigate the isoforms at the protein level. Reverse transcriptase PCR (RT-PCR) was applied to examine the sequence diversity. Eleven different variants of the deduced amino acid sequences were identified by RT-PCR. German cockroach tropomyosin has only minor sequence variations that did not seem to affect its allergenicity significantly. These results support the molecular basis underlying the cross-reactivities of arthropod tropomyosins. Recombinant fragments were also generated by PCR, and IgE-binding epitopes were assessed by enzyme-linked immunosorbent assay. Sera from seven patients revealed heterogeneous IgE-binding responses. This study demonstrates multiple IgE-binding epitope regions in a single molecule, suggesting that full-length tropomyosin should be used for the development of diagnostic and therapeutic reagents.
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16

Gunning, Peter W., and Edna C. Hardeman. "Tropomyosins." Current Biology 27, no. 1 (January 2017): R8—R13. http://dx.doi.org/10.1016/j.cub.2016.11.033.

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17

MacLeod, A. R., and C. Gooding. "Human hTM alpha gene: expression in muscle and nonmuscle tissue." Molecular and Cellular Biology 8, no. 1 (January 1988): 433–40. http://dx.doi.org/10.1128/mcb.8.1.433-440.1988.

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We have isolated a cDNA clone from a human skeletal muscle library which contains the complete protein-coding sequence of a skeletal muscle alpha-tropomyosin. This cDNA sequence defines a fourth human tropomyosin gene, the hTM alpha gene, which is distinct from the hTMnm gene encoding a closely related isoform of skeletal muscle alpha-tropomyosin. In cultured human fibroblasts, the hTM alpha gene encodes both skeletal-muscle- and smooth-muscle-type alpha-tropomyosins by using an alternative mRNA-splicing mechanism.
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18

MacLeod, A. R., and C. Gooding. "Human hTM alpha gene: expression in muscle and nonmuscle tissue." Molecular and Cellular Biology 8, no. 1 (January 1988): 433–40. http://dx.doi.org/10.1128/mcb.8.1.433.

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We have isolated a cDNA clone from a human skeletal muscle library which contains the complete protein-coding sequence of a skeletal muscle alpha-tropomyosin. This cDNA sequence defines a fourth human tropomyosin gene, the hTM alpha gene, which is distinct from the hTMnm gene encoding a closely related isoform of skeletal muscle alpha-tropomyosin. In cultured human fibroblasts, the hTM alpha gene encodes both skeletal-muscle- and smooth-muscle-type alpha-tropomyosins by using an alternative mRNA-splicing mechanism.
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19

Schrock, Dillon C. "Tropomyosins are critical mediators of CD8+ T cell synaptic actomyosin organization." Journal of Immunology 206, no. 1_Supplement (May 1, 2021): 14.05. http://dx.doi.org/10.4049/jimmunol.206.supp.14.05.

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Abstract CD8+ T cells are a critical arm of the adaptive immune system because they kill virally-infected and transformed cells. Their function is critically dependent on their ability to form stable interactions with antigen-presenting cells (APCs). These interactions are mediated by a highly-organized structure at the T cell: APC interface termed the immunological synapse (IS). The IS itself is organized largely by the underlying actin cytoskeleton. Perturbation of either the Arp2/3-dependent branched network of the distal region or of the formin-derived arc network of the peripheral region dampens TCR signaling and impairs subsequent T cell activation. Tropomyosins are actin-binding proteins that form head-to-tail polymers along the actin filament. Several tropomyosin isoforms associate preferentially with linear formin-generated filaments, such as those in the peripheral region of the IS, where they promote the recruitment and activation of myosin 2 and thwart cofilin-mediated severing. We have found that mouse CD8+ T cells express two prominent tropomyosin isoforms (Tpm3.1 and Tpm4.2) and that these isoforms are strongly upregulated following naïve cell activation. Interestingly, both of these isoforms have been associated with human pathology in proteomics experiments. Fluorescent-tagged versions of these tropomyosins colocalize with pSMAC actomyosin arcs and migrate toward the center of the IS. Importantly, treatment with an inhibitor of Tpm3.1, ATM3507, severely impacts the organization of T cell synaptic actin structures. Our aim is to examine the role that tropomyosins play in the organization of T cell synaptic actin and actomyosin structures and to determine their importance for effector function.
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20

Galán-Freyle, Nataly, Jesús Olivero-Verbel, and Liney Díaz-López. "Modeling of allergen proteins found in sea food products." Food Science and Technology 32, no. 2 (March 20, 2012): 393–400. http://dx.doi.org/10.1590/s0101-20612012005000032.

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Shellfish are a source of food allergens, and their consumption is the cause of severe allergic reactions in humans. Tropomyosins, a family of muscle proteins, have been identified as the major allergens in shellfish and mollusks species. Nevertheless, few experimentally determined three-dimensional structures are available in the Protein Data Base (PDB). In this study, 3D models of several homologous of tropomyosins present in marine shellfish and mollusk species (Chaf 1, Met e1, Hom a1, Per v1, and Pen a1) were constructed, validated, and their immunoglobulin E binding epitopes were identified using bioinformatics tools. All protein models for these allergens consisted of long alpha-helices. Chaf 1, Met e1, and Hom a1 had six conserved regions with sequence similarities to known epitopes, whereas Per v1 and Pen a1 contained only one. Lipophilic potentials of identified epitopes revealed a high propensity of hydrophobic amino acids in the immunoglobulin E binding site. This information could be useful to design tropomyosin-specific immunotherapy for sea food allergies.
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Bakin, Andrei V., Alfiya Safina, Cammie Rinehart, Cecilia Daroqui, Huferesh Darbary, and David M. Helfman. "A Critical Role of Tropomyosins in TGF-β Regulation of the Actin Cytoskeleton and Cell Motility in Epithelial Cells." Molecular Biology of the Cell 15, no. 10 (October 2004): 4682–94. http://dx.doi.org/10.1091/mbc.e04-04-0353.

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We have investigated transforming growth factor beta (TGF-β)–mediated induction of actin stress fibers in normal and metastatic epithelial cells. We found that stress fiber formation requires de novo protein synthesis, p38Mapk and Smad signaling. We show that TGF-β via Smad and p38Mapk up-regulates expression of actin-binding proteins including high-molecular-weight tropomyosins, α-actinin and calponin h2. We demonstrate that, among these proteins, tropomyosins are both necessary and sufficient for TGF-β induction of stress fibers. Silencing of tropomyosins with short interfering RNAs (siRNAs) blocks stress fiber assembly, whereas ectopic expression of tropomyosins results in stress fibers. Ectopic-expression and siRNA experiments show that Smads mediate induction of tropomyosins and stress fibers. Interestingly, TGF-β induction of stress fibers was not accompanied by changes in the levels of cofilin phosphorylation. TGF-β induction of tropomyosins and stress fibers are significantly inhibited by Ras-ERK signaling in metastatic breast cancer cells. Inhibition of the Ras-ERK pathway restores TGF-β induction of tropomyosins and stress fibers and thereby reduces cell motility. These results suggest that induction of tropomyosins and stress fibers play an essential role in TGF-β control of cell motility, and the loss of this TGF-β response is a critical step in the acquisition of metastatic phenotype by tumor cells.
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22

Mokronosova, Marina A., and Tatiana M. Zheltikova. "Clinical and immunological characteristics of sensitization to tropomyosins." Russian Journal of Allergy 18, no. 1 (March 15, 2021): 73–78. http://dx.doi.org/10.36691/rja1399.

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Tropomyosins are a family of allergenic proteins found in large quantities in all invertebrates. Tropomyosins sensitization causes a life-threatening allergic reaction up to anaphylaxis after eating seafood. Identifying the source of primary sensitization is important to predict the allergic reaction severity. This article describes a clinical case of chronic recurrent urticaria in an 8-year-old boy with tropomyosins sensitization. An 8-year-old boy was diagnosed with the following: controlled atopic phenotype bronchial asthma, food allergy (oral allergy syndrome), and chronic recurrent spontaneous urticaria. Component diagnostics revealed IgE-aB to tropomyosins in high concentrations from 38.79 to 43.38 kUA/l and cat and dog uteroglobin and lipocalins in high concentrations from 7.79 to 43.38 kUA/l. It is necessary to specify the primary sensitizer to analyze the clinical significance of allergens that provoke sensitization to various groups of allergens. In this case, sensitization to tropomyosins is most likely described as caused by either a helminthic invasion or midge bites. Therefore, food allergic reactions to tropomyosins caused from crustaceans were not observed.
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23

Kreuz, A. J., A. Simcox, and D. Maughan. "Alterations in flight muscle ultrastructure and function in Drosophila tropomyosin mutants." Journal of Cell Biology 135, no. 3 (November 1, 1996): 673–87. http://dx.doi.org/10.1083/jcb.135.3.673.

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Drosophila indirect flight muscle (IFM) contains two different types of tropomyosin: a standard 284-amino acid muscle tropomyosin, Ifm-TmI, encoded by the TmI gene, and two > 400 amino acid tropomyosins, TnH-33 and TnH-34, encoded by TmII. The two IFM-specific TnH isoforms are unique tropomyosins with a COOH-terminal extension of approximately 200 residues which is hydrophobic and rich in prolines. Previous analysis of a hypomorphic TmI mutant, Ifm(3)3, demonstrated that Ifm-TmI is necessary for proper myofibrillar assembly, but no null TmI mutant or TmII mutant which affects the TnH isoforms have been reported. In the current report, we show that four flightless mutants (Warmke et al., 1989) are alleles of TmI, and characterize a deficiency which deletes both TmI and TmII. We find that haploidy of TmI causes myofibrillar disruptions and flightless behavior, but that haploidy of TmII causes neither. Single fiber mechanics demonstrates that power output is much lower in the TmI haploid line (32% of wild-type) than in the TmII haploid line (73% of wild-type). In myofibers nearly depleted of Ifm-TmI, net power output is virtually abolished (< 1% of wild-type) despite the presence of an organized fibrillar core (approximately 20% of wild-type). The results suggest Ifm-TmI (the standard tropomyosin) plays a key role in fiber structure, power production, and flight, with reduced Ifm-TmI expression producing corresponding changes of IFM structure and function. In contrast, reduced expression of the TnH isoforms has an unexpectedly mild effect on IFM structure and function.
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24

Cooper, H. L., N. Feuerstein, M. Noda, and R. H. Bassin. "Suppression of tropomyosin synthesis, a common biochemical feature of oncogenesis by structurally diverse retroviral oncogenes." Molecular and Cellular Biology 5, no. 5 (May 1985): 972–83. http://dx.doi.org/10.1128/mcb.5.5.972-983.1985.

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To identify proteins whose production may be altered as a common event in the expression of structurally diverse oncogenes, we compared two-dimensional electropherograms of newly synthesized proteins from NIH/3T3 cell lines transformed by a variety of retroviral oncogenes, from cellular revertant lines, and from a line (433.3) which expresses the v-ras oncogene in response to corticosteroids. Most alterations in the synthesis of specific proteins detected by this approach appeared to be the result of selection during prolonged cultivation and were probably unrelated to the transformation process. However, we detected seven proteins whose synthesis was strongly suppressed in cell lines transformed by each of the six retroviral oncogenes we studied and whose production was fully or partially restored in two cellular revertant lines. Suppression of two of these proteins was also correlated with the initial appearance of morphological alteration during corticosteroid-induced oncogene expression in 433.3 cells. These proteins (p37/4.78 and p41/4.75) were identified as tropomyosins, a group of at least five cytoskeletal proteins. Transformation by the papovaviruses simian virus 40 and polyomavirus caused no suppression of synthesis of these tropomyosins. This indicates that suppression of tropomyosin synthesis is not a nonspecific response by cells to being forced to grow with the transformed phenotype but is specifically associated with oncogenesis by diverse retroviral oncogenes. The results are consistent with the hypothesis that the different biochemical processes initiated by expression of structurally diverse retroviral oncogenes may converge on a limited number of common targets, one of which is the mechanism which regulates the synthesis of tropomyosins.
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25

Cooper, H. L., N. Feuerstein, M. Noda, and R. H. Bassin. "Suppression of tropomyosin synthesis, a common biochemical feature of oncogenesis by structurally diverse retroviral oncogenes." Molecular and Cellular Biology 5, no. 5 (May 1985): 972–83. http://dx.doi.org/10.1128/mcb.5.5.972.

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To identify proteins whose production may be altered as a common event in the expression of structurally diverse oncogenes, we compared two-dimensional electropherograms of newly synthesized proteins from NIH/3T3 cell lines transformed by a variety of retroviral oncogenes, from cellular revertant lines, and from a line (433.3) which expresses the v-ras oncogene in response to corticosteroids. Most alterations in the synthesis of specific proteins detected by this approach appeared to be the result of selection during prolonged cultivation and were probably unrelated to the transformation process. However, we detected seven proteins whose synthesis was strongly suppressed in cell lines transformed by each of the six retroviral oncogenes we studied and whose production was fully or partially restored in two cellular revertant lines. Suppression of two of these proteins was also correlated with the initial appearance of morphological alteration during corticosteroid-induced oncogene expression in 433.3 cells. These proteins (p37/4.78 and p41/4.75) were identified as tropomyosins, a group of at least five cytoskeletal proteins. Transformation by the papovaviruses simian virus 40 and polyomavirus caused no suppression of synthesis of these tropomyosins. This indicates that suppression of tropomyosin synthesis is not a nonspecific response by cells to being forced to grow with the transformed phenotype but is specifically associated with oncogenesis by diverse retroviral oncogenes. The results are consistent with the hypothesis that the different biochemical processes initiated by expression of structurally diverse retroviral oncogenes may converge on a limited number of common targets, one of which is the mechanism which regulates the synthesis of tropomyosins.
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26

Palani, Saravanan, Darius V. Köster, Tomoyuki Hatano, Anton Kamnev, Taishi Kanamaru, Holly R. Brooker, Juan Ramon Hernandez-Fernaud, et al. "Phosphoregulation of tropomyosin is crucial for actin cable turnover and division site placement." Journal of Cell Biology 218, no. 11 (October 9, 2019): 3548–59. http://dx.doi.org/10.1083/jcb.201809089.

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Tropomyosin is a coiled-coil actin binding protein key to the stability of actin filaments. In muscle cells, tropomyosin is subject to calcium regulation, but its regulation in nonmuscle cells is not understood. Here, we provide evidence that the fission yeast tropomyosin, Cdc8, is regulated by phosphorylation of a serine residue. Failure of phosphorylation leads to an increased number and stability of actin cables and causes misplacement of the division site in certain genetic backgrounds. Phosphorylation of Cdc8 weakens its interaction with actin filaments. Furthermore, we show through in vitro reconstitution that phosphorylation-mediated release of Cdc8 from actin filaments facilitates access of the actin-severing protein Adf1 and subsequent filament disassembly. These studies establish that phosphorylation may be a key mode of regulation of nonmuscle tropomyosins, which in fission yeast controls actin filament stability and division site placement.
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27

Gunning, P. W., V. Ferguson, K. J. Brennan, and E. C. Hardeman. "Alpha-skeletal actin induces a subset of muscle genes independently of muscle differentiation and withdrawal from the cell cycle." Journal of Cell Science 114, no. 3 (February 1, 2001): 513–24. http://dx.doi.org/10.1242/jcs.114.3.513.

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Muscle differentiation is characterized by the induction of genes encoding contractile structural proteins and the repression of nonmuscle isoforms from these gene families. We have examined the importance of this regulated order of gene expression by expressing the two sarcomeric muscle actins characteristic of the differentiated state, i.e. alpha-skeletal and alpha-cardiac actin, in C2 mouse myoblasts. Precocious accumulation of transcripts and proteins for a group of differentiation-specific genes was elicited by alpha-skeletal actin only: four muscle tropomyosins, two muscle actins, desmin and MyoD. The nonmuscle isoforms of tropomyosin and actin characteristic of the undifferentiated state continued to be expressed, and no myosin heavy or light chain or troponin transcripts characteristic of muscle differentiation were induced. Stable transfectants displayed a substantial reduction in cell surface area and in the levels of nonmuscle tropomyosins and beta-actin, consistent with a relationship between the composition of the actin cytoskeleton and cell surface area. The transfectants displayed normal cell cycle progression. We propose that alpha-skeletal actin can activate a regulatory pathway linking a subset of muscle genes that operates independently of normal differentiation and withdrawal from the cell cycle.
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28

Watakabe, A., R. Kobayashi, and D. M. Helfman. "N-tropomodulin: a novel isoform of tropomodulin identified as the major binding protein to brain tropomyosin." Journal of Cell Science 109, no. 9 (September 1, 1996): 2299–310. http://dx.doi.org/10.1242/jcs.109.9.2299.

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We have identified and characterized two proteins in rat brain that bind to the neuron-specific tropomyosin isoform, TMBr3. The two proteins were identified by blot overlay assay, in which the proteins immobilized on the membrane were probed by epitope-tagged TMBr3, followed by detection with anti-epitope antibody. We have purified these proteins using a TMBr3 affinity column. Peptide sequencing as well as immunoblotting showed that one of the two proteins is identical to tropomodulin, a tropomyosin-binding protein originally identified in erythrocytes. The cDNA for the other protein was cloned from an adult rat brain cDNA library using degenerate oligonucleotides that we designed based on the peptide sequences. Sequence analysis of the cDNA clone revealed this protein to be a novel isoform of tropomodulin which is the product of a distinct gene, and is herein referred to as N-tropomodulin. Recombinant N-tropomodulin bound to TMBr3 as well as to other low molecular mass tropomyosins (TM5a or TM5), but not to high molecular mass tropomyosins (TM2 or TMBr1). Northern blotting and RNase protection assays as well as immunoblotting showed that N-tropomodulin is expressed predominantly in brain. Furthermore, RNase protection assays revealed no alternatively spliced regions within the coding sequence. Developmentally, N-tropomodulin was detected in rat brain as early as embryonic day 14 and reaches the adult level before birth. Immunofluorescence of primary frontal cortex cell cultures showed that N-tropomodulin is specifically expressed in neurons. The neuron-specific expression of N-tropomodulin strongly suggests specialized roles of this TM-binding protein in neurons.
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29

González-Fernández, Juan, Beatriz Veleiro, Alvaro Daschner, and Carmen Cuéllar. "Are fish tropomyosins allergens?" Annals of Allergy, Asthma & Immunology 116, no. 1 (January 2016): 74–76. http://dx.doi.org/10.1016/j.anai.2015.09.017.

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30

Hu, Shiqiong, Hanna Grobe, Zhenhuan Guo, Yu-Hsiu Wang, Bryant L. Doss, Meng Pan, Benoit Ladoux, Alexander D. Bershadsky, and Ronen Zaidel-Bar. "Reciprocal regulation of actomyosin organization and contractility in nonmuscle cells by tropomyosins and alpha-actinins." Molecular Biology of the Cell 30, no. 16 (July 22, 2019): 2025–36. http://dx.doi.org/10.1091/mbc.e19-02-0082.

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Contractile arrays of actin and myosin II filaments drive many essential processes in nonmuscle cells, including migration and adhesion. Sequential organization of actin and myosin along one dimension is followed by expansion into a two-dimensional network of parallel actomyosin fibers, in which myosin filaments are aligned to form stacks. The process of stack formation has been studied in detail. However, factors that oppose myosin stack formation have not yet been described. Here, we show that tropomyosins act as negative regulators of myosin stack formation. Knockdown of any or all tropomyosin isoforms in rat embryonic fibroblasts resulted in longer and more numerous myosin stacks and a highly ordered actomyosin organization. The molecular basis for this, we found, is the competition between tropomyosin and alpha-actinin for binding actin. Surprisingly, excessive order in the actomyosin network resulted in smaller focal adhesions, lower tension within the network, and smaller traction forces. Conversely, disordered actomyosin bundles induced by alpha-actinin knockdown led to higher than normal tension and traction forces. Thus, tropomyosin acts as a check on alpha-actinin to achieve intermediate levels of myosin stacks matching the force requirements of the cell.
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31

Had, L., C. Faivre-Sarrailh, C. Legrand, J. Mery, J. Brugidou, and A. Rabie. "Tropomyosin isoforms in rat neurons: the different developmental profiles and distributions of TM-4 and TMBr-3 are consistent with different functions." Journal of Cell Science 107, no. 10 (October 1, 1994): 2961–73. http://dx.doi.org/10.1242/jcs.107.10.2961.

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Antipeptide antisera specific for TM-4 and TMBr-3, the two tropomyosin isoforms in neurons, were used to investigate the concentrations and distributions of these F-actin-binding proteins in neurons in vitro and in vivo. TM-4 and TMBr-3 tropomyosins had different developmental profiles. TM-4 was found mainly in immature stages, while the concentration of TMBr-3 increased with maturation. The two isoforms also had different subcellular distributions. TM-4 was concentrated in the growth cones of cultured neurons and, in vivo, in areas where neurites were growing. Later, when development was complete, TM-4 was restricted to postsynaptic sites in the cerebellar cortex, whereas TMBr-3 was found in the presynaptic terminals. These data suggest that the tropomyosin isoforms have different functions, through their interaction with the actin cytoskeleton. TM-4 may be involved in the motile events of neurite growth and synaptic plasticity, while TMBr-3 could play a role in stabilizing neuronal networks and synaptic functioning.
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32

Borovikov, Yurii, Olga Karpicheva, Armen Simonyan, Stanislava Avrova, Elena Rogozovets, Vladimir Sirenko, and Charles Redwood. "The Primary Causes of Muscle Dysfunction Associated with the Point Mutations in Tpm3.12; Conformational Analysis of Mutant Proteins as a Tool for Classification of Myopathies." International Journal of Molecular Sciences 19, no. 12 (December 10, 2018): 3975. http://dx.doi.org/10.3390/ijms19123975.

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Point mutations in genes encoding isoforms of skeletal muscle tropomyosin may cause nemaline myopathy, cap myopathy (Cap), congenital fiber-type disproportion (CFTD), and distal arthrogryposis. The molecular mechanisms of muscle dysfunction in these diseases remain unclear. We studied the effect of the E173A, R90P, E150A, and A155T myopathy-causing substitutions in γ-tropomyosin (Tpm3.12) on the position of tropomyosin in thin filaments, and the conformational state of actin monomers and myosin heads at different stages of the ATPase cycle using polarized fluorescence microscopy. The E173A, R90P, and E150A mutations produced abnormally large displacement of tropomyosin to the inner domains of actin and an increase in the number of myosin heads in strong-binding state at low and high Ca2+, which is characteristic of CFTD. On the contrary, the A155T mutation caused a decrease in the amount of such heads at high Ca2+ which is typical for mutations associated with Cap. An increase in the number of the myosin heads in strong-binding state at low Ca2+ was observed for all mutations associated with high Ca2+-sensitivity. Comparison between the typical conformational changes in mutant proteins associated with different myopathies observed with α-, β-, and γ-tropomyosins demonstrated the possibility of using such changes as tests for identifying the diseases.
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33

Palani, Saravanan, Darius Koester, and Mohan K. Balasubramanian. "Phosphoregulation of tropomyosin-actin interaction revealed using a genetic code expansion strategy." Wellcome Open Research 5 (July 7, 2020): 161. http://dx.doi.org/10.12688/wellcomeopenres.16082.1.

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Tropomyosins are coiled-coil proteins that regulate the stability and / or function of actin cytoskeleton in muscle and non-muscle cells through direct binding of actin filaments. Recently, using the fission yeast, we discovered a new mechanism by which phosphorylation of serine 125 of tropomyosin (Cdc8), reduced its affinity for actin filaments thereby providing access for the actin severing protein Adf1/Cofilin to actin filaments causing instability of actin filaments. Here we use a genetic code expansion strategy to directly examine this conclusion. We produced in Escherichia coli Cdc8-tropomyosin bearing a phosphate group on Serine-125 (Cdc8PS125), using an orthogonal tRNA-tRNA synthetase pair that directly incorporates phosphoserine into proteins in response to a UAG codon in the corresponding mRNA. We show using total internal reflection (TIRF) microscopy that, whereas E.coli produced Cdc8PS125 does not bind actin filaments, Cdc8PS125 incubated with lambda phosphatase binds actin filaments. This work directly demonstrates that a phosphate moiety present on serine 125 leads to decreased affinity of Cdc8-tropomyosin for actin filaments. We also extend the work to demonstrate the usefulness of the genetic code expansion approach in imaging actin cytoskeletal components.
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34

Weinberger, R. P., R. C. Henke, O. Tolhurst, P. L. Jeffrey, and P. Gunning. "Induction of neuron-specific tropomyosin mRNAs by nerve growth factor is dependent on morphological differentiation." Journal of Cell Biology 120, no. 1 (January 1, 1993): 205–15. http://dx.doi.org/10.1083/jcb.120.1.205.

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We have examined the expression of brain-specific tropomyosins during neuronal differentiation. Both TmBr-1 and TmBr-3 were shown to be neuron specific. TmBr-1 and TmBr-3 mRNA levels increased during the most active phase of neurite outgrowth in the developing rat cerebellum. In PC12 cells stimulated by nerve growth factor (NGF) to differentiate to the neuronal phenotype, TmBr-1 and TmBr-3 levels increased with an increasing degree of morphological differentiation. Induction of TmBr-1 and TmBr-3 expression only occurred under conditions where PC12 cells were permitted to extend neurites. NGF was unable to maintain levels of TmBr-1 and TmBr-3 with the loss of neuronal phenotype by resuspension of differentiated PC12 cells. The unique cellular expression and regulation in vivo and in vitro of TmBr-1 and TmBr-3 strongly suggests a critical role of these tropomyosins in neuronal microfilament function. The findings reveal that the induction and maintenance of the neuronal tropomyosins is dependent on morphological differentiation and the maintenance of the neuronal phenotype.
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35

Suma, Yota, Shoichiro Ishizaki, Yuji Nagashima, Ying Lu, Hideki Ushio, and Kazuo Shiomi. "Comparative analysis of barnacle tropomyosin: Divergence from decapod tropomyosins and role as a potential allergen." Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 147, no. 2 (June 2007): 230–36. http://dx.doi.org/10.1016/j.cbpb.2007.01.004.

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36

Yong Jeong, Kyoung, Chein-Soo Hong, and Tai-Soon Yong. "Allergenic Tropomyosins and Their Cross-Reactivities." Protein & Peptide Letters 13, no. 8 (August 1, 2006): 835–45. http://dx.doi.org/10.2174/092986606777841244.

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37

Arruda, L. Karla. "The Right Timing for Shrimp Tropomyosins." International Archives of Allergy and Immunology 160, no. 4 (November 21, 2012): 331–33. http://dx.doi.org/10.1159/000345363.

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38

Ferraz, Conchita, Joannes Sri Widada, and Jean-Pierre Liautard. "Purification and characterization of recombinant tropomyosins." Journal of Chromatography A 539, no. 2 (January 1991): 465–73. http://dx.doi.org/10.1016/s0021-9673(01)83956-x.

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39

Vejborg, R. M., N. Bernbom, L. Gram, and P. Klemm. "Anti-adhesive properties of fish tropomyosins." Journal of Applied Microbiology 105, no. 1 (July 2008): 141–50. http://dx.doi.org/10.1111/j.1365-2672.2007.03718.x.

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40

Swenson, Charles A., and Nancy C. Stellwagen. "Flexibility of smooth and skletal tropomyosins." Biopolymers 28, no. 5 (May 1989): 955–63. http://dx.doi.org/10.1002/bip.360280504.

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41

NOVY, R., L. LIU, C. LIN, D. HELFMAN, and J. LIN. "Expression of smooth muscle and nonmuscle tropomyosins in Escherichia coli and characterization of bacterially produced tropomyosins." Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology 1162, no. 3 (March 26, 1993): 255–65. http://dx.doi.org/10.1016/0167-4838(93)90289-4.

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42

Jeong, Kyoung Yong, Heeyu Hwang, Jongweon Lee, In-Yong Lee, Dong Soo Kim, Chein-Soo Hong, Han-Il Ree, and Tai-Soon Yong. "Allergenic Characterization of Tropomyosin from the Dusky Brown Cockroach, Periplaneta fuliginosa." Clinical Diagnostic Laboratory Immunology 11, no. 4 (July 2004): 680–85. http://dx.doi.org/10.1128/cdli.11.4.680-685.2004.

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ABSTRACTHousehold arthropods are one of the most common causes of allergic diseases. Four species of cockroaches are found to reside in Korean homes, but published work deals almost exclusively with the German and American cockroaches. This study was undertaken to investigate the cross-reactive allergenic components of the dusky brown cockroach,Periplaneta fuliginosa. Enzyme-linked immunosorbent assay (ELISA) inhibition and immunoblot analyses for the dusky brown cockroach were performed withBlattella germanicaandDermatophagoides farinaeallergic sera. cDNA encoding tropomyosin, which is a well known cross-reactive pan-allergen, was cloned by reverse transcriptase PCR, and recombinant protein was produced by using a pET-28b expression system. Native tropomyosin was purified by ammonium sulfate fractionation and electroelution. The immunoglobulin E (IgE) reactivities of native and recombinant tropomyosins were compared by an ELISA inhibition study. All 30 sera tested showedP. fuliginosa-specific IgE, and the IgE-binding reactivity of theP. fuliginosaextract was inhibited as much as 79.4% by aB. germanicaextract and as much as 63.3% by aD. farinaeextract. The deduced amino acid sequence of cloned cDNA was identical with that ofPeriplaneta americanatropomyosin (98.5% nucleotide sequence identity). Seven of 26 (26.9%) allergic sera had IgE specific for recombinant protein, and the maximum inhibition ofP. fuliginosa-specific IgE achieved with recombinant tropomyosin was 37.7% at an inhibitor concentration of 10 μg/ml. Native tropomyosin inhibited the binding of IgE to theP. fuliginosa,B. germanica, andD. farinaeextracts by 65.0, 51.8, and 39% at an inhibitor concentration of 1 μg/ml.P. fuliginosaappears to possess allergens that are highly cross-reactive with allergens ofB. germanicaandD. farinae. Tropomyosin was found to be a major allergenic component accounting for the cross-reactivity between cockroaches and dust mites.
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43

Côté, A., J. P. Doucet, and J. M. Trifaró. "Adrenal Medullary Tropomyosins: Purification and Biochemical Characterization." Journal of Neurochemistry 46, no. 6 (October 5, 2006): 1771–82. http://dx.doi.org/10.1111/j.1471-4159.1986.tb08495.x.

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44

Fath, Thomas. "Tropomodulins and tropomyosins – organizers of cellular microcompartments." BioMolecular Concepts 4, no. 1 (February 1, 2013): 89–101. http://dx.doi.org/10.1515/bmc-2012-0037.

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AbstractEukaryotic cells show a remarkable compartmentalization into compartments such as the cell nucleus, the Golgi apparatus, the endoplasmic reticulum, and endosomes. However, organelle structures are not the only means by which specialized compartments are formed. Recent research shows a critical role for diverse actin filament populations in defining functional compartments, here referred to as microcompartments, in a wide range of cells. These microcompartments are involved in regulating fundamental cellular functions including cell motility, plasma membrane organization, and cellular morphogenesis. In this overview, the importance of two multigene families of actin-associated proteins, tropomodulins and tropomyosins, their interactions with each other, and a large number of other proteins will be discussed in the context of generating specialized actin-based microcompartments.
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Araya, Esteban, Christine Berthier, Edward Kim, Trevor Yeung, Xiaorong Wang, and David M. Helfman. "Regulation of Coiled-Coil Assembly in Tropomyosins." Journal of Structural Biology 137, no. 1-2 (January 2002): 176–83. http://dx.doi.org/10.1006/jsbi.2002.4463.

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46

Colpan, Mert, Natalia A. Moroz, and Alla S. Kostyukova. "Tropomodulins and tropomyosins: working as a team." Journal of Muscle Research and Cell Motility 34, no. 3-4 (July 5, 2013): 247–60. http://dx.doi.org/10.1007/s10974-013-9349-6.

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47

Jeong, Kyoung Yong, Hye-Yung Yum, In-Yong Lee, Han-Il Ree, Chein-Soo Hong, Dong Soo Kim, and Tai-Soon Yong. "Molecular Cloning and Characterization of Tropomyosin, a Major Allergen of Chironomus kiiensis, a Dominant Species of Nonbiting Midges in Korea." Clinical Diagnostic Laboratory Immunology 11, no. 2 (March 2004): 320–24. http://dx.doi.org/10.1128/cdli.11.2.320-324.2004.

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ABSTRACT Chironomids are widely and abundantly distributed in the vicinity of standing waters. Larvae of Chironomus and some other genera are known to contain hemoglobins, which have been described as a major allergen, and the adults that have no hemoglobins also have been reported to contain allergens. In this study, we tried to establish the role of chironomid allergy and characterize the allergen of Chironomus kiiensis adults. Skin tests using C. kiiensis adult extracts were performed on patients with allergic symptoms. A cDNA library of C. kiiensis adults was screened with C. kiiensis immune mouse sera to identify allergens, and results were confirmed using skin test-positive human sera. Recombinant allergen was expressed in Escherichia coli and purified by affinity chromatography using nickel-nitrilotriacetic acid agarose to investigate its allergenic properties. Out of 275 allergic patients 14.2% showed a positive reaction to C. kiiensis adult crude extracts in the skin test. The tropomyosin was cloned by immunoscreening and expressed in Escherichia coli. C. kiiensis tropomyosin has a high homology at the amino acid level with tropomyosins which were previously known to be allergens in various arthropods (Periplaneta americana, 86.3%; Panulirus stimpson, 78.9%; Dermatophagoides pteronyssinus, 76.5%). Specific immunoglobulin E antibodies reacting to recombinant tropomyosin were detected in 17 (81%) of 21 patients whose skin test results were positive. Cross-reactivity against house dust mites and other insects was noticed with mouse anti-recombinant tropomyosin immune serum. C. kiiensis adults were shown to be an important source of inhalant allergens in Korea. Molecular cloning of C. kiiensis tropomyosin was performed and IgE reactivity was demonstrated using skin test-positive human sera. Recombinant tropomyosin will be useful for further studies or clinical applications.
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48

Bach, Cuc T. T., Sarah Creed, Jessie Zhong, Maha Mahmassani, Galina Schevzov, Justine Stehn, Lauren N. Cowell, et al. "Tropomyosin Isoform Expression Regulates the Transition of Adhesions To Determine Cell Speed and Direction." Molecular and Cellular Biology 29, no. 6 (January 5, 2009): 1506–14. http://dx.doi.org/10.1128/mcb.00857-08.

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ABSTRACT The balance of transition between distinct adhesion types contributes to the regulation of mesenchymal cell migration, and the characteristic association of adhesions with actin filaments led us to question the role of actin filament-associating proteins in the transition between adhesive states. Tropomyosin isoform association with actin filaments imparts distinct filament structures, and we have thus investigated the role for tropomyosins in determining the formation of distinct adhesion structures. Using combinations of overexpression, knockdown, and knockout approaches, we establish that Tm5NM1 preferentially stabilizes focal adhesions and drives the transition to fibrillar adhesions via stabilization of actin filaments. Moreover, our data suggest that the expression of Tm5NM1 is a critical determinant of paxillin phosphorylation, a signaling event that is necessary for focal adhesion disassembly. Thus, we propose that Tm5NM1 can regulate the feedback loop between focal adhesion disassembly and focal complex formation at the leading edge that is required for productive and directed cell movement.
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49

Robaszkiewicz, Katarzyna, Małgorzata Śliwinska, and Joanna Moraczewska. "Regulation of Actin Filament Length by Muscle Isoforms of Tropomyosin and Cofilin." International Journal of Molecular Sciences 21, no. 12 (June 16, 2020): 4285. http://dx.doi.org/10.3390/ijms21124285.

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In striated muscle the extent of the overlap between actin and myosin filaments contributes to the development of force. In slow twitch muscle fibers actin filaments are longer than in fast twitch fibers, but the mechanism which determines this difference is not well understood. We hypothesized that tropomyosin isoforms Tpm1.1 and Tpm3.12, the actin regulatory proteins, which are specific respectively for fast and slow muscle fibers, differently stabilize actin filaments and regulate severing of the filaments by cofilin-2. Using in vitro assays, we showed that Tpm3.12 bound to F-actin with almost 2-fold higher apparent binding constant (Kapp) than Tpm1.1. Cofilin2 reduced Kapp of both tropomyosin isoforms. In the presence of Tpm1.1 and Tpm3.12 the filaments were longer than unregulated F-actin by 25% and 40%, respectively. None of the tropomyosins affected the affinity of cofilin-2 for F-actin, but according to the linear lattice model both isoforms increased cofilin-2 binding to an isolated site and reduced binding cooperativity. The filaments decorated with Tpm1.1 and Tpm3.12 were severed by cofilin-2 more often than unregulated filaments, but depolymerization of the severed filaments was inhibited. The stabilization of the filaments by Tpm3.12 was more efficient, which can be attributed to lower dynamics of Tpm3.12 binding to actin.
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50

Drees, B. "Distinct and essential functions of tropomyosins in yeast." Trends in Cell Biology 5, no. 5 (May 1995): 195. http://dx.doi.org/10.1016/s0962-8924(00)88996-5.

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