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Academic literature on the topic 'PIP5K1'

Author: Grafiati

Published: 7 October 2023

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Journal articles on the topic "PIP5K1"

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Kawase, Atsushi, Yuta Inoue, Miho Hirosoko, Yuka Sugihara, Hiroaki Shimada, and Masahiro Iwaki. "Decrease in Multidrug Resistance-associated Protein 2 Activities by Knockdown of Phosphatidylinositol 4-phosphate 5-kinase in Hepatocytes and Cancer Cells." Journal of Pharmacy & Pharmaceutical Sciences 22 (November 19, 2019): 576–84. http://dx.doi.org/10.18433/jpps30444.

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Purpose: The plasma membrane localization and transport activity of multidrug resistance-associated protein 2 (MRP2/ABCC2) and P-glycoprotein (P-gp/ABCB1) efflux transporters are governed by transporter-associated proteins. Phosphatidylinositol 4,5-bisphosphate (PIP2) formed by phosphatidylinositol 4-phosphate 5-kinase type 1 (PIP5K1) activates the linker function of radixin for efflux transporters. Radixin is involved in the plasma membrane localization of efflux transporters. We examined whether PIP5K1 could be a target for the modulation of transporter activities in hepatocytes and cancer cells. Methods: The effects of PIP5K1 depletion by siRNA in mouse primary hepatocytes, PANC1 human pancreatic carcinoma cells, and HepG2 human hepatocellular carcinoma cells on the intracellular accumulation of MRP2 and P-gp substrates were examined. Results: PIP5K1A depletion resulted in increased intracellular accumulation of carboxydichlorofluorescein, a MRP2 fluorescent substrate, in mouse primary hepatocytes, PANC1 cells, and HepG2 cells. In PANC1 and HepG2 cells, the transport activities of MRP2 were significantly decreased by PIP5K1C depletion. However, the transport activities of P-gp were unchanged by PIP5K1 depletion. PIP2 levels were unchanged between control and PIP5K1A- or PIP5K1C-depleted HepG2 cells. MRP2 mRNA levels showed few changes in HepG2 cells following PIP5K1A or PIP5K1C depletion. The expression of phosphorylated radixin was decreased by PIP5K1A and PIP5K1C depletion, although total radixin levels were unchanged. Conclusions: These data suggest that PIP5K1A and PIP5K1C could be target proteins for modulating MRP2 function, partly because of the resulting changes of the linker function of radixin.

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Wright, Brittany D., Catherine Simpson, Michael Stashko, Dmitri Kireev, Emily A. Hull-Ryde, Mark J. Zylka, and William P. Janzen. "Development of a High-Throughput Screening Assay to Identify Inhibitors of the Lipid Kinase PIP5K1C." Journal of Biomolecular Screening 20, no. 5 (December 22, 2014): 655–62. http://dx.doi.org/10.1177/1087057114564057.

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Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) regulate a variety of cellular processes, including signaling through G protein-coupled receptors (GPCRs), endocytosis, exocytosis, and cell migration. These lipid kinases synthesize phosphatidylinositol 4,5-bisphosphate (PIP2) from phosphatidylinositol 4-phosphate [PI(4)P]. Because small-molecule inhibitors of these lipid kinases did not exist, molecular and genetic approaches were predominantly used to study PIP5K1 regulation of these cellular processes. Moreover, standard radioisotope-based lipid kinase assays cannot be easily adapted for high-throughput screening. Here, we report a novel, high-throughput, microfluidic mobility shift assay to identify inhibitors of PIP5K1C. This assay uses fluorescently labeled phosphatidylinositol 4-phosphate as the substrate and recombinant human PIP5K1C. Our assay exhibited high reproducibility, had a calculated adenosine triphosphate Michaelis constant (Km) of 15 µM, performed with z’ values >0.7, and was used to screen a kinase-focused library of ~4700 compounds. From this screen, we identified several potent inhibitors of PIP5K1C, including UNC3230, a compound that we recently found can reduce nociceptive sensitization in animal models of chronic pain. This novel assay will allow continued drug discovery efforts for PIP5K1C and can be adapted easily to screen additional lipid kinases.

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Khadka, Bijendra, and Radhey S. Gupta. "Novel Molecular Signatures in the PIP4K/PIP5K Family of Proteins Specific for Different Isozymes and Subfamilies Provide Important Insights into the Evolutionary Divergence of this Protein Family." Genes 10, no. 4 (April 21, 2019): 312. http://dx.doi.org/10.3390/genes10040312.

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Members of the PIP4K/PIP5K family of proteins, which generate the highly important secondary messenger phosphatidylinositol-4,5-bisphosphate, play central roles in regulating diverse signaling pathways. In eukaryotic organisms, multiple isozymes and subfamilies of PIP4K/PIP5K proteins are found and it is of much interest to understand their evolution and species distribution and what unique molecular and biochemical characteristics distinguish specific isozymes and subfamilies of proteins. We report here the species distribution of different PIP4K/PIP5K family of proteins in eukaryotic organisms and phylogenetic analysis based on their protein sequences. Our results indicate that the distinct homologs of both PIP4K and PIP5K are found in different organisms belonging to the Holozoa clade of eukaryotes, which comprises of various metazoan phyla as well as their close unicellular relatives Choanoflagellates and Filasterea. In contrast, the deeper-branching eukaryotic lineages, as well as plants and fungi, contain only a single homolog of the PIP4K/PIP5K proteins. In parallel, our comparative analyses of PIP4K/PIP5K protein sequences have identified six highly-specific molecular markers consisting of conserved signature indels (CSIs) that are uniquely shared by either the PIP4K or PIP5K proteins, or both, or specific subfamilies of these proteins. Of these molecular markers, 2 CSIs are distinctive characteristics of all PIP4K homologs, 1 CSI distinguishes the PIP4K and PIP5K homologs from the Holozoa clade of species from the ancestral form of PIP4K/PIP5K found in deeper-branching eukaryotic lineages. The remaining three CSIs are specific for the PIP5Kα, PIP5Kβ, and PIP4Kγ subfamilies of proteins from vertebrate species. These molecular markers provide important means for distinguishing different PIP4K/PIP5K isozymes as well as some of their subfamilies. In addition, the distribution patterns of these markers in different isozymes provide important insights into the evolutionary divergence of PIP4K/PIP5K proteins. Our results support the view that the Holozoa clade of eukaryotic organisms shared a common ancestor exclusive of the other eukaryotic lineages and that the initial gene duplication event leading to the divergence of distinct types of PIP4K and PIP5K homologs occurred in a common ancestor of this clade. Based on the results gleaned from different studies presented here, a model for the evolutionary divergence of the PIP4K/PIP5K family of proteins is presented.

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Wang, Yanfeng, Lurong Lian, Aae Suzuki, Rustem I. Litvinov, Timothy J. Stalker, Alec A. Schmaier, Lawrence F. Brass, John Weisel, and Charles S. Abrams. "Loss of Individual PIP5KI Isoforms Demonstrate That Spatial PIP2 Synthesis Is Required for Platelet Second Messenger Formation & Integrity of the Actin Cytoskeleton." Blood 112, no. 11 (November 16, 2008): 109. http://dx.doi.org/10.1182/blood.v112.11.109.109.

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Abstract Following thrombin stimulation, platelet PIP5KI synthesizes phosphatidylinositol 4,5-bisphosphate (PIP2), which can be hydrolyzed by phospholipase C to generate second messengers such as IP3. PIP2 also regulates cytoskeletal dynamics by directly interacting with actin-binding proteins. Three isoforms of PIP5KI (α, β, and γ) are all capable of phosphorylating PI4P to synthesize PIP2. However, these isoforms have different primary structures, expression levels in various tissues, and intracellular localization. We have generated and characterized murine lines lacking PIP5KIβ or PIP5KIγ, which are the two predominant platelet isoforms. We also phenotyped platelets lacking PIP5KIα, which is the least abundant isoform. PIP5KIβ-null mice appeared developmentally normal and had normal platelet counts, however they had small defects in aggregation following exposure to all agonists. In contrast, platelets lacking PIP5KIα aggregated normally. Although platelets lacking PIP5KIβ have only a moderate deficiency of PIP2 under basal conditions, they have a striking deficiency in PIP2 synthesis and IP3 formation following thrombin stimulation. We have also observed that platelets lacking both PIP5KIα and PIP5KIβ have a complete loss of thrombin-induced IP3 synthesis, even though they still contain PIP5KIγ, which is the predominant PIP5KI isoform in platelets. Additionally, we found when using a carotid injury model that PIP5KIβ-null platelets failed to properly form arterial thrombi in vivo. This demonstrates that PIP5KIβ, like PIP5KIα, contributes to the rapid synthesis of a pool of PIP2 that is required for second messenger formation and in vivo platelet adhesion. This contrasts the PIP5KIγ-synthesized pool of PIP2 that does not contribute to these processes. We have found that loss of PIP5KIγ null mutation impairs cardiac development and leads to embryonic lethality. PIP5KIγ null megakaryocytes derived from yolk sac progenitor cells have a defect in anchoring their cell membranes to the underlying actin cytoskeleton. To understand the role of this PIP5KI isoform in platelet biology, we conditionally rescued the PIP5KIγ null mutation within myocardiocytes allowing us to obtain living mice. Platelets from these animals lacked PIP5KIγ, yet aggregated normally when exposed to all agonists. To analyze these cells for a failure to anchor their cell membranes, we used laser tweezers to pull the cell membrane apart from the cytoskeleton. Wild type cells had rigid membranes that resisted stretching by trapped fibrinogen-coated beads that were pulled by laser tweezers. In contrast, the PIP5KIγ-null platelets had flexible membranes that were easily stretched, and ultimately allowed membrane tethers to form. Together, these results demonstrate that following stimulation of a G-protein coupled receptor, IP3 is completely derived from a rapidly synthesized discrete pool of PIP2 that is synthesized by PIP5KIα and PIP5KIβ. In contrast, the pool of PIP2 synthesized by PIP5KIγ contributes to preserving the integrity of the membrane cytoskeleton. In conclusion, this work demonstrates that spatially restricted PIP2 synthesis by individual PIP5KI isoforms differentially controls second messenger formation and the integrity of the actin cytoskeleton.

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Padrón, David, Ying Jie Wang, Masaya Yamamoto, Helen Yin, and Michael G. Roth. "Phosphatidylinositol phosphate 5-kinase Iβ recruits AP-2 to the plasma membrane and regulates rates of constitutive endocytosis." Journal of Cell Biology 162, no. 4 (August 11, 2003): 693–701. http://dx.doi.org/10.1083/jcb.200302051.

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Overexpression of phosphatidylinositol phosphate 5-kinase (PIP5KI) isoforms α, β, or γ in CV-1 cells increased phosphatidylinositol 4,5-bisphosphate (PIP2) levels by 35, 180, and 0%, respectively. Endocytosis of transferrin receptors, association of AP-2 proteins with membranes, and the number of clathrin-coated pits at the plasma membrane increased when PIP2 increased. When expression of PIP5KIβ was inhibited with small interference RNA in HeLa cells, expression of PIP5KIα was also reduced slightly, but PIP5KIγ expression was increased. PIP2 levels and internalization of transferrin receptors dropped 50% in these cells; thus, PIP5KIγ could not compensate for loss of PIP5KIβ. When expression of PIP5KIα was reduced, expression of both PIP5KIβ and PIP5KIγ increased and PIP2 levels did not change. A similar increase of PIP5KIα and PIP5KIβ occurred when PIP5KIγ was inhibited. These results indicate that constitutive endocytosis in CV-1 and HeLa cells requires (and may be regulated by) PIP2 produced primarily by PIP5KIβ.

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Clarke, Jonathan H., Piers C. Emson, and Robin F. Irvine. "Localization of phosphatidylinositol phosphate kinase IIγ in kidney to a membrane trafficking compartment within specialized cells of the nephron." American Journal of Physiology-Renal Physiology 295, no. 5 (November 2008): F1422—F1430. http://dx.doi.org/10.1152/ajprenal.90310.2008.

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PIP4Ks (type II phosphatidylinositol 4-phosphate kinases) are phosphatidylinositol 5-phosphate (PtdIns5P) 4-kinases, believed primarily to regulate cellular PtdIns5P levels. In this study, we investigated the expression, localization, and associated biological activity of the least-studied PIP4K isoform, PIP4Kγ. Quantitative RT-PCR and in situ hybridization revealed that compared with PIP4Kα and PIP4Kβ, PIP4Kγ is expressed at exceptionally high levels in the kidney, especially the cortex and outer medulla. A specific antibody was raised to PIP4Kγ, and immunohistochemistry with this and with antibodies to specific kidney cell markers showed a restricted expression, primarily distributed in epithelial cells in the thick ascending limb and in the intercalated cells of the collecting duct. In these cells, PIP4Kγ had a vesicular appearance, and transfection of kidney cell lines revealed a partial Golgi localization (primarily the matrix of the cis-Golgi) with an additional presence in an unidentified vesicular compartment. In contrast to PIP4Kα, bacterially expressed recombinant PIP4Kγ was completely inactive but did have the ability to associate with active PIP4Kα in vitro. Overall our data suggest that PIP4Kγ may have a function in the regulation of vesicular transport in specialized kidney epithelial cells.

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Bultsma, Yvette, Willem-Jan Keune, and Nullin Divecha. "PIP4Kβ interacts with and modulates nuclear localization of the high-activity PtdIns5P-4-kinase isoform PIP4Kα." Biochemical Journal 430, no. 2 (August 13, 2010): 223–35. http://dx.doi.org/10.1042/bj20100341.

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The β-isoform of PIP4K (PtdIns5P-4-kinase) regulates the levels of nuclear PtdIns5P, which in turn modulates the acetylation of the tumour suppressor p53. The crystal structure of PIP4Kβ demonstrated that it can form a homodimer with the two subunits arranged in opposite orientations. Using MS, isoform-specific antibodies against PIP4Ks, RNAi (RNA interference) suppression and overexpression studies, we show that PIP4Kβ interacts in vitro and in vivo with the PIP4Kα isoform. As the two isoforms phosphorylate the same substrate to generate the same product, the interaction could be considered to be functionally redundant. However, contrary to expectation, we find that PIP4Kβ has 2000-fold less activity towards PtdIns5P compared with PIP4Kα, and that the majority of PIP4K activity associated with PIP4Kβ comes from its interaction with PIP4Kα. Furthermore, PIP4Kβ can modulate the nuclear localization of PIP4Kα, and PIP4Kα has a role in regulating PIP4Kβ functions. The results of the present study suggest a rationale for the functional interaction between PIP4Kα and PIP4Kβ and provide insight into how the relative levels of the two enzymes may be important in their physiological and pathological roles.

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Chen, Xinsheng, Yanfeng Wang, Tami L. Bach, Lurong Lian, Rustem I. Litvinov, John W. Weisel, and Charles S. Abrams. "Mice Lacking PIP5Kβ or PIP5Kγ Have Unique Cytoskeletal Changes within Their Megakaryocytes & Platelets." Blood 106, no. 11 (November 16, 2005): 380. http://dx.doi.org/10.1182/blood.v106.11.380.380.

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Abstract Phosphatidylinositol-4, 5-bisphosphate (PIP2) is vital for the signaling cascades that are critical for actin dynamics. Although all PIP5K isoforms (α , β , and γ ) synthesize PIP2 by phosphorylating PI4P, the isoforms have different primary structures, expression levels in various tissues, and intracellular localization. To test the hypothesis that the functions of these isoforms are also different, we have generated murine lines that contain null mutations in either of two platelet PIP5K isoforms, PIP5Kβ and PIP5Kγ . PIP5Kβ -null mice were born 42% less than anticipated by Mendelian genetics, and heterozygotes were born 18% less than the expected frequency. Adult PIP5Kβ −/− mice had normal platelet counts and exhibited no spontaneous hemorrhage. However, PIP5Kβ −/− platelets had impaired aggregation in response to thrombin and thromboxane analogues. In addition, following agonist stimulation they failed to properly synthesize additional PIP2. Platelets lacking PIP5Kβ also exhibited a marked defect in spreading upon immobilized fibrinogen. This failure to spread was associated with a striking decrease in filopodia formation and extension of actin rich lamellipodia. In contrast to the phenotype of PIP5Kβ -knockout mice, we found that targeted disruption of PIP5Kγ results in early prenatal mortality due to a cardiovascular developmental defect. This early lethality prevented studies of hematopoietic cells derived from the bone marrow or the liver. However, we were able to analyze yolk sac progenitor cells that were treated with thrombopoietin ex vivo, differentiating them into megakaryocytes. Similar to PIP5Kβ knockout megakaryocytes, PIP5Kγ knockout megakaryocytes had normal basal levels of PIP2, but decreased synthesis following stimulation with thrombin. Using spinning disk video confocal microscopy, we examined membrane dynamics during cell adhesion in real time. Wild type megakaryocytes actively formed and contracted lamellipodia, and rapidly spread upon the fibrinogen matrix. In contrast, PIP5Kγ -null megakaryocytes continuously extended and retracted membrane blebs, rather than lamellipodia, but eventually spread as much as wild type cells. This observation is consistent with the previous suggestion that PIP2 contributes to the stable association of the membrane with the cytoskeleton. Using laser tweezers to pull the cell membrane apart from the cytoskeleton, we found that long tethers of the membrane could easily be drawn from PIP5Kγ −/− megakaryocytes, but not from PIP5Kγ +/− or PIP5Kβ −/− megakaryocytes. This implies that PIP5Kγ −/− megakaryocytes have a defect in their ability to anchor the cell membrane to the cytoskeleton. This defect was attributable to the ability of PIP5Kγ to synthesize PIP2 since it could be rescued by adding back wild type PIP5Kγ , but could not be rescued by a catalytically inactive PIP5Kγ mutant. Accordingly, our data are consistent with the hypothesis that different PIP5K isoforms contribute to compartmentalized pools of PIP2 that contribute to different aspect of platelet &megakaryocyte actin dynamics. PIP5Kβ synthesizes PIP2 that contributes to the formation of filopodia and lamellipodia, while PIP5Kγ generates PIP2 that is required for the stable association of the membrane with the cytoskeleton.

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Wang, Yanfeng, Aae Suzuki, Lurong Lian, Rustem I. Litvinov, Timothy J. Stalker, John K. Choi, John W. Weisel, Lawrence F. Brass, and Charles S. Abrams. "Platelets Lacking PIP5KIγ Have Impaired Cytoskeletal Dynamics and Adhesion, but No Defect in Integrin Activation." Blood 114, no. 22 (November 20, 2009): 772. http://dx.doi.org/10.1182/blood.v114.22.772.772.

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Abstract Abstract 772 Following thrombin stimulation, platelet PIP5KI synthesizes phosphatidylinositol 4,5-bisphosphate (PIP2), which can be hydrolyzed by phospholipase C to generate second messengers such as IP3. PIP2 also regulates cytoskeletal dynamics by directly interacting with actin-binding proteins such as talin. Three isoforms of PIP5KI (α, β, and γ) are all capable of phosphorylating PI4P to synthesize PIP2. We have generated and characterized murine lines lacking individual PIP5KI isoforms. While mice lacking PIP5KIα and PIP5KIα have absent second messenger formation and partially impaired integrin activation, they are viable. In contrast, mice lacking PIP5KIγ die in utero due to a cardiovascular developmental defect. Megakaryocytes derived from PIP5KIγ-null embryos bleb their membranes due to impaired anchoring of the cell membrane with the underlying cytoskeleton. Since platelets can not be obtained from these embryos, we employed a genetic approach. We used a MLC-2v Cre transgene that targets Cre expression to myocytes, and generated living mice lacking PIP5KIγ by a conditional rescue. PIP5KIγ-/- MLC-2v Cre+ mice expressed PIP5KIγ in the myocardium, but they had absent expression of PIP5KIγ in all other analyzed tissue. These mice had normal appearing hearts, brains, livers, and bone marrow morphology, as well as normal platelet counts. Since mice lacking PIP5KIα and PIP5KIβ have impaired platelet PIP2 production that causes absent IP3 formation, we analyzed platelets lacking PIP5KIγ for second messenger formation. Even though PIP5KIγ an abundant PIP5KI isoform in platelets, loss of PIP5KIγ does not affect IP3 formation or Akt phosphorylation. It has been previously demonstrated that PIP5KIγ can directly bind talin, a protein that regulates the function of integrins. An existing proposed model for integrin activation is that talin-associated PIP5KIγ synthesize PIP2. This newly synthesized PIP2 then binds a FERM domain within talin. The model suggests that this complex of PIP5KIγ-PIP2-talin is critical for the final step that stimulates integrins to bind their ligand. We found three lines of evidence that disprove this model of integrin activation. First, we found that PIP5KIγ-/- platelets had normal integrin-mediated aggregation in response to all analyzed doses of thrombin, ADP, collagen, and a thromboxane analogue (U46619). Second, we observed that PIP5KIγ-null platelets exhibited normal binding of Jon/A, an antibody that recognizes only the activated form of αIIb/β3. Third, we determined that platelets lacking PIP5KIγ spread normally upon adherent fibrinogen. Together, these results disprove the existing model that PIP5KIγ is a critical component of talin-mediated integrin activation. To determine the true function of PIP5KIγ within platelets, we extended our previous studies by analyzing the role PIP5KIγ plays in the regulation of the cytoskeleton. Therefore, we analyzed platelets lacking this enzyme for their ability to anchor the cytoskeleton to the cell membrane. We used optical tweezers to pull the cell membrane apart from the cytoskeleton. Wild type cells had rigid membranes that resisted stretching by trapped fibrinogen-coated beads that were pulled by the optical trap. In contrast, the PIP5KIγ-null platelets had flexible membranes that were easily stretched, and ultimately allowed membrane tethers to form. We further analyzed whether this defect in anchoring the cell membrane to the underlying cytoskeleton causes a defect in vivo using a carotid artery arterial injury model. Mice lacking platelet PIP5KIγ exhibited unstable adhesion in vivo suggesting that impaired cytoskeletal dynamics causes impaired platelet adhesion under flow. Together, our studies demonstrate that the abundant PIP5KI isoform, PIP5KIγ does not contribute to a pool of PIP2 required for second messenger formation or integrin activation. However it does synthesize the pool of PIP2 required to preserve the integrity of the membrane cytoskeleton, and support stable platelet adhesion under conditions of shear. Disclosures: No relevant conflicts of interest to declare.

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Drake, J. M., and J. Huang. "PIP5K1 inhibition as a therapeutic strategy for prostate cancer." Proceedings of the National Academy of Sciences 111, no. 35 (August 12, 2014): 12578–79. http://dx.doi.org/10.1073/pnas.1413363111.

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Dissertations / Theses on the topic "PIP5K1"

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黒田, 凌. "シロイヌナズナにおけるPIP5K7,PIP5K8およびPIP5K9の機能解析." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/264646.

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Liu, Chen [Verfasser], and Anton [Akademischer Betreuer] Schäffner. "The PIP1 protein expression is positively regulated by PIP2;1 and PIP2;2 in Arabidopsis thaliana / Chen Liu. Betreuer: Anton Schäffner." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1078852243/34.

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Gonzales, Baptiste. "Etudes des facteurs cellulaires et lipidiques déterminant la localisation du site d'assemblage et de bourgeonnement du VIH-1." Electronic Thesis or Diss., Tours, 2019. http://www.theses.fr/2019TOUR3811.

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La formation des particules du VIH-1 résulte de l'assemblage des précurseurs Gag sur le feuillet interne de la membrane plasmique (MP) des cellules infectées. Les protéines Gag sont spécifiquement adressées à la MP grâce à des interactions entre le domaine MA et le PI(4,5)P2. Cette étude décrit le rôle des phosphadidylinosito1-4-phosphate 5-kinase de type 1 (PIP5K1alpha, beta et sigma) au cours des étapes tardives du VIH-1 dans le modèle celllulaire HeLa. Nous avons démontré que la PIP5K1alpha est l'enzyme principalement impliquée dans la production du PI(4,5P2. En suivant le trafic de Gag à la MP. Leur inhibition respective induit l'accumulation des précurseurs viraux dans les compartiments intracellulaires distincts et diminue la libération des pseudo-particules Gag dans les deux cas. L'ensemble de nos résultats démontre pour la première fois l'importance de l'activité des PIP5K1alpha et sigma dans l'assemblage et le bourgeonnement du VIH-1 et fournit de nouveaux éléments utiles à la compréhension des étapes tardives du cycle de multiplication viral
The production pocesses of HIV-1 particle of HIV-1 particles results from the assembly of Gag Precursors at the inner leaflet of the plasma membrane (PM) of infected cells. Gag proteins are specifically targeted to PM through interactions between MA domain and PI(4,5)P2. This study describes the role of phosphatidylinositol-4-phosphate 5-kinase type 1 (PIP5K1alpha, beta et sigma) in the late stages of HIV-1 in the context of HeLa cells. We determined that PIP5K1alpha is the principal producer of cellular PI(4,5)P2. By using a confocal microscopy approach, we followed the Gag proteins trafficking and showed that only alpha and y isoforms are required for the correct targeting of Gag to PM. Their respective inhibition leads to the accumulation of viral precursors at distinct intracellular comprtements, and decreases the release of Gag pseudoparticles in both cases. Altogether, our results highlight for the first time the crucial role PIP5K1alpha and sigma in the HIV-1 assembly and budding and provide new insights for a better understanding of the late stages of the virus replication cycle

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Champeyroux, Chloé. "Caractérisation fonctionnelle de protéines en interaction avec l'aquaporine PIP2;1." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT120.

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La conductivité hydraulique racinaire (Lpr) traduit la capacité de transport d’eau de la racine. Lors de son trajet du sol vers le xylème, l’eau diffuse au sein de l’apoplasme ou au travers des cellules (voie de cellule-à-cellule). Au niveau de l’endoderme, la diffusion apoplasmique de l’eau est bloquée par le cadre de Caspari et des lamelles de subérine. La voie de cellule-à-cellule dépend principalement de l’activité des aquaporines régulées en partie par des interactions protéiques. Ce travail caractérise de nouveaux interactants de l’aquaporine racinaire PIP2;1 : le récepteur kinase RKL1 et 4 protéines de fonction inconnue appartenant à la sous-famille 1 des Casparian Strip membrane domain Protein Like (CASPL1) (CASPL1-B1/B2/D1/D2). RKL1 est exprimée dans l’endoderme, est capable d’interagir physiquement avec PIP2;1 et stimule in vitro le transport d’eau par l’aquaporine. Cependant, l’inactivation de RKL1 n’affecte pas la Lpr sans que cela ne puisse être expliqué par une redondance fonctionnelle avec son plus proche homologue, RLK902. Une étude bibliographique suggère que l’interaction entre RKL1 et PIP2;1 interviendrait dans une voie de signalisation en réponse à une attaque pathogène. Concernant les CASPL, D1 est exprimé dans tous les tissus, alors que B1, B2 et D2 semblent uniquement exprimés dans des territoires subérisés. Ce profil suggère une implication de B1, B2 et D2 dans une régulation des aquaporines et de la subérisation. Au niveau moléculaire, D2, malgré son interaction physique avec PIP2;1, ne module pas le transport d’eau par l’aquaporine. En revanche, B1 interagit préférentiellement avec PIP2;1 sous une forme phosphorylée et stimule le transport d’eau par l’aquaporine. Au niveau de la plante entière, l’inactivation d’un ou deux gènes CASPL n’affecte ni la Lpr., ni la subérisation. Par contre, l’inactivation de PIP2;1 et PIP2;2 révèle un effet inhibiteur de ces aquaporines sur la subérisation. Cette étude a permis de décrire de nouveaux mécanismes originaux de régulation des aquaporines. Elle pose également, la question de l’existence d’une relation entre les transports d’eau par la voie apoplasmique et par les aquaporines
The root hydraulic conductivity (Lpr) reflects the water transport capacity of the root. During its transfer from the soil to the xylem, water can diffuse in the apoplasm or through the cells (cell-to-cell pathway). At the endodermis, the apoplastic diffusion of water is blocked by the Casparian Strip and suberin lamellae. The cell-to-cell pathway mainly relies on aquaporin activity which can be regulated by protein interactions. This study aims at characterizing new interactants of the root aquaporin PIP2;1: the receptor kinase RKL1 and 4 proteins of unknown function belonging to the Casparian Strip membrane domain Protein Like 1 sub-family (CASPL1-B1/B2/D1/D2). RKL1 is expressed in the endodermis, can physically interact with PIP2;1 and stimulates its water transport function in vitro. However a loss-of-function of RKL1 does not affect the Lpr., independently of a putative functional redundancy with its closest homolog RLK902. Concerning CASPL, D1 is expressed in every tissue of the root whereas B1, B2 and D2 appear to be specifically expressed in suberized tissues. This suggests a putative role of these isoforms in aquaporin regulation and suberisation. At the molecular level, D2 does not modulate PIP2;1 water transport activity despite a physical interaction between the two partners. By contrast, B1 interacts with PIP2;1 preferentially in its phosphorylated form and enhances the water transport activity of the aquaporin. At the plant level, disrupting one or two CASPL genes neither impact the Lpr nor affect the suberisation. However, the loss of function of both PIP2;1 and PIP2;2 reveals a negative effect of these aquaporins on suberisation. In conclusion, this study, uncovered novel regulation mechanisms of aquaporins. It also raises the question of the existence of a putative relationship between water transport by the apoplastic pathway and by aquaporins

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Kurenbach, Brigitta. "Konjugativer DNA-Transfer zwischen Gram-positiven und Gram-negativen Spezies: Transferkomponenten des Multiresistenzplasmids pIP501 aus Streptococcus agalactiae." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971485305.

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Toscano, Sarah. "Functional characterisation of PIP4K in Drosophila melanogaster." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609822.

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Tavelis, Christodoulos. "Investigating the potential role of PIP4Ks in PI3K/Akt signalling." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/investigating-the-potential-role-of-pip4ks-in-pi3kakt-signalling(e70d9473-5932-468a-bdad-01668a68db58).html.

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Class I phosphoinositide 3-kinases (PI3Ks) generate the essential lipid second messenger PtdIns(3,4,5)P3 which plays a key role in the regulation of numerous cellular processes including cell growth and survival, gene transcription, cytoskeletal organisation and glucose metabolism through its downstream effectors and in particular the serine/threonine protein kinase Akt. Therefore, the PI3K/Akt signalling plays a critical regulatory role in diverse cellular processes and its dysregulation is implicated in the pathogenesis of many human diseases including cancer and type 2 diabetes. Overexpression of phosphatidylinositol-5-phosphate 4-kinase β (PIP4Kβ), a lipid kinase which phosphorylates the poorly understood phosphoinositide phospholipid PtdIns5P to produce PtdIns(4,5)P2, has been demonstrated to lead to the attenuation of PtdIns(3,4,5)P3 levels and decreased Akt phosphorylation in insulin-stimulated cells. Conversely, mice lacking PIP4Kβ exhibit increased insulin-induced Akt phosphorylation, suggesting a potential role of PIP4Ks in the regulation of PI3K/Akt signalling. The aim of this project was to investigate the potential role of PIP4Kα, the most active isoform among PIP4Ks, in the regulation of PI3K/Akt signalling and whether its substrate, PtdIns5P, is involved in this regulation.While YM201636, an inhibitor of PIKfyve an enzyme believed to be involved in PtdIns5P production, markedly reduced Akt phosphorylation in PDGF-stimulated NIH/3T3 cells, contrary to expectations, overexpression of PIP4Kα in NIH/3T3 and HeLa S3 cells had no effect on PtdIns(3,4,5)P3 levels or Akt phosphorylation upon stimulation with PDGF and IGF-1 respectively. However, PtdIns(3,4,5)P3 levels were significantly decreased in insulin-stimulated L6 myotubes overexpressing PIP4Kα, indicating a possible cell type specific modulation of PI3K signalling by PIP4Kα. Interestingly, despite the decreased PtdIns(3,4,5)P3 levels, insulin-stimulated Akt phosphorylation remained unaffected in PIP4Kα expressing L6 myotubes. PIP4Kα overexpression also resulted in increased levels of PtdIns(3,4)P2. This suggests an increased 5-dephosphorylation of PtdIns(3,4,5)P3 through the action of one or more 5-phosphatases. Although the precise 5-phosphatase(s) are not known, the data indicate that this cannot be SHIP2 which has previously been implicated in the regulation of PtdIns(3,4,5)P3 levels in insulin signalling. Taken together, the data presented in this thesis indicate a role for PIP4Kα in PI3K signalling in a cell type specific manner. This might have important physiological implications.

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Jouette, Julie. "Phosphoinositides et contrôle de la polarité cellulaire : régulations croisées entre la PIP5K Skittles et les protéines de polarité PAR1 et PAR3." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC118.

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La polarité cellulaire est un processus fondamental qui contrôle les spécificités fonctionnelle et physiologique de la plupart des cellules eucaryotes. Cette asymétrie intracellulaire repose sur l’existence de compartiments membranaires distincts, à la fois dans leur composition en protéines mais également en phosphatidyl-inositols (PIs). Ainsi, la mise en place et le maintien de la localisation asymétrique de modules multi-protéiques associés notamment aux protéines PAR sont essentiels pour l’élaboration des domaines de polarité cellulaire. Durant ma thèse, j’ai étudié les relations entre les protéines de polarité et les PIs dans le contrôle de la polarité cellulaire. Plus particulièrement, en utilisant la chambre ovarienne de Drosophile, j’ai cherché à caractériser la suite d’évènements qui en amont régule l’activité de la PIP5K, Skittles (SKTL), qui produit le PI(4,5)P2 et à caractériser les mécanismes moléculaires qui lient le PI(4,5)P2, SKTL et les protéines PAR dans le contrôle et le maintien de la polarité cellulaire. J’ai contribué à caractériser l’importance de PI(4,5)P2 majoritairement produit par SKTL, dans le maintien de la polarité apico-basale et lors de la morphogenèse des cellules folliculaires de la chambre ovarienne. Le PI(4,5)P2 assure la localisation apicale de PAR3 et le maintien des jonctions adhérentes, sans affecter la localisation de PAR1. Par une méthode de quantification précise, j’ai ensuite démontré dans l’ovocyte que SKTL et le PI(4,5)P2, probablement grâce au trafic vésiculaire, étaient requis pour à la fois l’accumulation à l’antérieur de PAR3 et son exclusion au postérieur qui se fait à partir du stade 9B. L’accumulation antérieure de PAR3 est également dépendante d’un transport Dynéine dépendant et de la kinase IKKε tandis que son exclusion postérieure dépendant des phosphorylations par PAR1. Enfin, j’ai également étudié les modifications post traductionnelles de SKTL et leur importance dans la polarité cellulaire. J’ai identifié la présence de palmitoylation et de phosphorylations dont certaines impliquent la kinase PAR1 et la phosphatase PP1. Ces phosphorylations pourraient avoir un lien avec le rôle de SKTL dans le trafic vésiculaire. Ces résultats permettent donc d’élucider certains mécanismes cellulaires qui contrôlent la mise en place et le maintien de la polarité des cellules en liant les PIs et les protéines PAR
Cell polarity is a fundamental process that controls cell’s functional and physiological specificities. This process relies on membranous compartments differently composed both on proteins and on phosphatidyl-inositols (PIs). Indeed, through their asymmetric localization, polarity proteins, such as the PAR proteins, are essentials to establish and maintain polarity of the cells. During my PhD, I studied the interplay between the polarity proteins and the PIs. Using the Drosophila egg chamber, as a model, I aimed to characterized the upstream events that regulate the PI(4,5)P2 producing kinase (PIP5K), Skittles (SKTL), activity and localization. I also studied the downstream molecular process that link the PI(4,5)P2, SKTL and the PAR proteins in cell polarity. I contributed to the characterization of the importance of PI(4,5)P2, mainly produced by SKTL in maintaining the apical-basal polarity and during the morphogenesis of the follicle cells. The PI(4,5)P2 is ensuring PAR3 and adherens junctions but not PAR1 proper localizations. Next, through a precise quantification method, I showed that SKTL and the PI(4,5)P2, probably via vesicular traffic, were also ensuring PAR3 proper localizations (anterior accumulation and stage 9B posterior exclusion) in the oocyte. PAR3 accumulation also relies on a Dynein mediated transport and the IKKε kinase while its posterior exclusion relies on PAR1 phosphorylation. Finally, I studied SKTL post translational modifications and their relevance on cell polarity. I identified palmitoylation and phosphorylations that are regulated by the kinase PAR1 and the phosphatase PP1. SKTL phosphorylations seem to be related to its role on the vesicular traffic. Altogether these results clarify some mechanisms involving both PIs and PAR proteins in cell polarity maintaining and establishment

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Gerth, Angela Katharina [Verfasser]. "Phosphoinositide im Kern pflanzlicher Zellen : Kernlokalisierung der ubiquitären PI4P 5-Kinase PIP5K2 und ihr Einfluss auf die Entwicklung von Arabidopsis thaliana / Angela Katharina Gerth." Halle, 2018. http://d-nb.info/1155760921/34.

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Othman, Arige. "Pharmacomodulation on the piperidinol skeleton: Synthesis of novel PIPD1 derivatives as Mycobacterium abscessus agents." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13396/.

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Mycobacterium abscessus (M. abscessus) is a rapidly growing mycobacterium which is able to generate different problems in human infections, such as chronic lung diseases, pulmonary diseases and skin infection. M. abscessus is considered as the first emergent opportunistic pathogen and the number of the infections due to this pathogen increases each year. Since the natural multidrug resistance and the absence of specific treatment to fight it, M. abscessus has become a serious problem of the public health. In this context, an original approach of a phenotypic screen was performed and allowed to identify a new piperidinol-based molecule, PIPD1, which exhibits a potent activity against M. abscessus. The goal of this project was to synthesize and characterize some PIPD1-analogs in order to identify the pharmacophore of PIPD1 and develop a Structure-Activity Relationship (SAR) study.

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Books on the topic "PIP5K1"

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Kadir, Tulus Handra. Teknik interlocking dalam gaya permainan talempong Minangkabau di Desa Kubang Pipik, Kecamatan Baso, Kabupaten Agam, Propinsi Sumatera Barat: Laporan penelitian. [Padang]: Universitas Negeri Padang, 2002.

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Book chapters on the topic "PIP5K1"

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Donato, Dominique M., Steven K. Hanks, Kenneth A. Jacobson, M. P. Suresh Jayasekara, Zhan-Guo Gao, Francesca Deflorian, John Papaconstantinou, et al. "PIP5K2." In Encyclopedia of Signaling Molecules, 1429. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_101045.

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Donato, Dominique M., Steven K. Hanks, Kenneth A. Jacobson, M. P. Suresh Jayasekara, Zhan-Guo Gao, Francesca Deflorian, John Papaconstantinou, et al. "PIP4K." In Encyclopedia of Signaling Molecules, 1429. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_101044.

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Mei, Yu. "Arabidopsis PIP5K2 Is Involved in Salt Tolerance." In Functional Characterization of Arabidopsis Phosphatidylinositol Monophosphate 5-kinase 2 in Lateral Root Development, Gravitropism and Salt Tolerance, 63–77. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9373-5_5.

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Mei, Yu. "Structure and Expression Pattern Analysis of Arabidopsis PIP5K2." In Functional Characterization of Arabidopsis Phosphatidylinositol Monophosphate 5-kinase 2 in Lateral Root Development, Gravitropism and Salt Tolerance, 17–28. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9373-5_2.

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Halstead, Jonathan R., Mireille H. Snel, Sarah Meeuws, David R. Jones, and Nullin Divecha. "Assaying Endogenous Phosphatidylinositol-4-Phosphate 5-Kinase (PIP5K) Activities." In Methods in Molecular Biology, 1–12. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-60327-115-8_25.

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Gonçalves, João, Helena Soares, Norman L. Eberhardt, Sarah C. R. Lummis, David R. Soto-Pantoja, David D. Roberts, Umadas Maitra, et al. "Type II PIPK." In Encyclopedia of Signaling Molecules, 1943. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_101423.

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Mei, Yu. "Arabidopsis PIP5K2 Is Involved in Lateral Root Development Through Regulating Auxin Accumulation." In Functional Characterization of Arabidopsis Phosphatidylinositol Monophosphate 5-kinase 2 in Lateral Root Development, Gravitropism and Salt Tolerance, 29–43. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9373-5_3.

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Mei, Yu. "Arabidopsis PIP5K2 Is Involved in Root Gravitropism Through Regulation of Polar Auxin Transport." In Functional Characterization of Arabidopsis Phosphatidylinositol Monophosphate 5-kinase 2 in Lateral Root Development, Gravitropism and Salt Tolerance, 45–62. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9373-5_4.

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"PIP5K2." In Encyclopedia of Signaling Molecules, 4023. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_102917.

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"PIP4K2." In Encyclopedia of Signaling Molecules, 4023. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_102916.

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Conference papers on the topic "PIP5K1"

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El-Awaad, Ehab, Katja Strätker, Samer Haidar, Ángel Amesty, Claudia Götz, Ana Estévez-Braun, and Joachim Jose. "Targeting lipid kinase PIP5K1α as a promising strategy for the treatment of castration-resistant prostate cancer." In 6th International Electronic Conference on Medicinal Chemistry. Basel, Switzerland: MDPI, 2020. http://dx.doi.org/10.3390/ecmc2020-07466.

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Wu, Pingping, Yue Teng, Ning Gu, Kecen Lu, Huayun Zhu, and Yajing Wang. "PIP5KL1: A Novel Diagnostic and Prognostic Marker for Colorectal Cancer : A novel diagnostic and prognostic marker." In 2022 16th ICME International Conference on Complex Medical Engineering (CME). IEEE, 2022. http://dx.doi.org/10.1109/cme55444.2022.10063305.

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