Thèses sur le sujet « BAG3 protein »

Membrane compartmentalisation allows eukaryotic cells to perform complex processes by combining dedicated sets of proteins in the same organelle. To achieve this, the cell must first target the appropriate proteins, primarily synthesised on cytosolic ribosomes, to the correct subcellular location. Components of the secretory pathway/endomembrane system begin this journey via their signal sequence-dependent delivery to the endoplasmic reticulum (ER). These ER targeting signals are hydrophobic, and typically function whilst the protein is being synthesised, via a so-called 'co-translational' pathway. However, some hydrophobic signals can also facilitate post-translational protein targeting to the ER, or initiate regulated protein degradation in the cytosol. Tail-anchored (TA) proteins are transmembrane proteins with a single C-terminal transmembrane domain that functions as both their subcellular targeting signal and membrane anchor. Recent evidence suggests that the canonical TRC40 pathway, through which mammalian TA proteins are delivered to the ER, may not be essential in vivo. In this thesis, I provide functional evidence for the existence of an orthologous SRP-independent (SND) pathway in mammalian cells and identify roles for both the signal recognition particle (SRP)-mediated pathway and presumptive mammalian SND pathway in the biogenesis of TA proteins. I conclude that although TRC40 normally plays a role in TA protein biogenesis, it is not essential, and speculate that these alternative pathways make a significant contribution to the apparent redundancy of the TRC40 pathway in vivo. The soluble components that act upstream of TRC40 during protein biogenesis also play an important role in the recognition and selective degradation of hydrophobic membrane and secretory proteins that mislocalise to the cytosol. I now provide preliminary evidence that TRC40 appears to exhibit dual functionality, having a non-essential role in TA protein delivery, whilst also contributing to protein quality control by acting as a putative holdase. My data suggest that both TRC40 and BAG6 can influence the proteasomal degradation of a novel class of substrates, which I have termed the aberrant short secretory proteins.

The incidence of epidermal squamous cell carcinoma (SCC) has increased significantly over recent years, largely due to increased exposure to its major aetiological factor, UVB radiation. Despite its increasing prevalence, relatively little is known regarding the genetic changes involved in SCC development. The aim of this study was to investigate the potential involvement of the anti-apoptotic protein BcI-2-associated athanogene-l (Bag-i), which shows deregulated expression in a range of human tumours, in epidermal SCC development, in addition to investigating a potential functional role for Bag-l in the epidermal response to UVB radiation. Expression of Bag-l and its key interaction partner Hsp70, which is associated with Bag-l anti- apoptotic function, was investigated in a panel of 60 epidermal SCCs and 10 samples of normal epidermal epithelium. Bag-l expression was deregulated in a subset of tumours compared with normal epidermis, with high Bag-l protein levels associated with reduced tumour differentiation. A positive correlation was observed between cytoplasmic expression of Bag-l and Hsp70, with strong Hsp70 staining also correlating with reduced tumour differentiation. In an attempt to investigate potential functional consequences of elevated Bag-l expression in epidermal tumours, the role of Bag-l in the keratinocyte response to UVB was investigated using the non-tumorigenic, spontaneously immortalised HaCaT cell line as a model system. siRNA-mediated Bag-l knockdown sensitised HaCaT cells to UVB-induced apoptosis, implicating an anti-apoptotic role for Bag-l in this context. The anti-apoptotic function of Bag-l was found to involve the Bag-iS protein isoform, using' stablv-Bag-LS transfected clones of the HaCaT cell line, in addition to transient overexpression of Bag-iS using an adenoviral vector. Bag-l anti- apoptotic function was dependent on amino acid residues required for Hsp70 and Raf-l binding. In HaCaT cells, UVB-irradiation resulted in downregulation of anti-apoptotic McI-l 2 to 8 hours post-irradiation. Levels of the BH3-only pro-apoptotic proteins Bim and Noxa were elevated at 24 hours and 6 to 24 hours post-irradiation, respectively. Overexpression of Bag-iS attenuated UVB-induced McI-l protein reduction, highlighting a potential role for Bag-l in control of McI-l levels. Further to this, a pilot study of 8 samples of normal epidermal epithelium and 14 SCCs highlighted potential overexpression of McI-l in epidermal tumours compared with normal epidermis. The results presented in this thesis demonstrate that expression of Bag-l and Hsp70 is deregulated in epidermal SCC, implicating the Bag-l:Hsp70 axis as a potential novel therapeutic target. Elevated Bag-l expression in epidermal SCC may be associated with its role in protection against apoptosis induced by UVB irradiation in epidermal keratinocytes. Bag-l anti-apoptotic function in this context appears to be mediated, at least in part, via control of levels ofthe anti-apoptotic protein McI-1. Further to its role in protection against UVB-induced apoptosis, an anti-apoptotic role for Bag-l was identified in the response to the chemotherapeutic drug 5-fluorouracil in the SCC-13 epidermal SCC cell line. Levels of Bag-l in epidermal SCC may therefore affect the tumour response to chemotherapeutic agents.

In this Master’s Thesis Research the results can be summarized from two major tasks: (1) In our first task, we utilized our two protein system (BAG-1 and HSP 70) as part of beta testing of a computational software 1 that can take three dimensional x-ray crystallography information about protein complexes and predict the strength of atom –atom interactions between amino-acid residues Open Contact predicts binding hotspots that can be used to identify short amino acid chains or peptides that mimic that particular binding segment of the larger protein. These peptides are called pepidyl-biomimetics. The peptide can potentially act as an antagonist drug by binding to the hotspot on protein A before protein B of the A-B complex can form. Two potential peptide candidates were identified. In particular, a helical peptide was discovered that demonstrated a variety of different types of atom-atom interactions. (2) Our second task is to experimentally test the helical peptide for its ability to block the binding that occurs between the 70-kilodalton Heat Shock Protein (HSP-70) and the Bcl-2 Associated Athanogene (BAG-1) Protein. As reviewed here, the binding between HSP-70 and BAG-1 elicits a cascade of cellular events that maintain high cancer growth rates and a greatly increased resistance to chemotherapy. In addition, BAG-1 has been implicated in a number of onco-signal pathways, as reviewed here, and its inhibition alone is believed to act as an agent against cancer cell growth

Bcl-2 associated AthanoGene-1 (BAG-1) is a multifunctional protein competent to delay cell death by a synergistic action with Bcl-2. BAG-1, as well as Bcl-2, has been reported as deregulated in diverse cancer types. During PhD study, we confirmed BAG-1 protein as over-expressed in a cohort of leukemic cell lines and heterogeneously expressed in patients affected by de novo acute myeloid or lymphoid leukemia. Silencing approach, used for a determination of BAG-1’s role in AML, suggested a correlation between BAG-1 down-regulation and decreased expression of certain proteins, which contribution to a proliferative advantage of leukemic cells has already been documented. BAG-1 expression in leukemic cells was demonstrated to be reciprocally regulated with the expression of BAG-3, gene from the same family which shows functional similarities with BAG-1. In correspondence, major impact on leukemic cell faith was verified by co-silencing both of this genes. The increased cell death, confirmed after co-silencing of leukemic cell lines and primary AML, was sustained by caspase-3 and PARP cleavage and release of cytochrome c and Smac/DIABLO. Key effect of BAG-1 and BAG-3 co-silencing was seen at the levels of anti-apoptotic proteins Bcl-2, Mcl-1 and Bcl-XL, survival protein ERK1/2 and cyclin D1, which all resulted as decreased. Our results indicated that BAG-1 might take an important place in a protection of native Bcl-2 and Mcl-1 proteins from a proteasome derived degradation, since proteins became removed from cell more intensively after transient BAG-1;3 silencing. In consequence, BAG-1, sustained by BAG-3, occurred to be a novel protein able to affect leukemic cells faith when highly expressed, in major part by provoking in these cells a block of apoptosis induction. It is most likely that described role BAG-1 accomplishes either directly or indirectly. In fact, BAG-1 interacts directly with Bcl-2 and most likely with Usp9X, influencing thereby indirectly the expression of Mcl-1, protein of great importance for leukemic blasts survival, and in consequence impairing the apoptosis induction. Finally, BAG-1 and BAG-3 seem to be new molecules capable to sustain AML. Therefore, identification of their molecular targets, such as Bcl-2, Mcl-1 and Usp9X, significant for leukemia development, gives a meaning to the novel pathways which could be of importance for paediatric AML development and opens a possibility for the future studies for a new therapeutic targets.<br>Bcl-2 associated AthanoGene-1 (BAG-1) è una proteina multifunzionale competente per ritardare la morte cellulare mediante un'azione sinergica principalmente con Bcl-2. BAG-1 così come Bcl-2, è stato segnalato essere molto spesso deregolato in diversi tipi di cancro. Durante il dottorato di ricerca, abbiamo trovato che la proteina BAG-1 è sovra-espressa in una coorte di linee cellulari leucemiche e si esprime in modo eterogeneo in pazienti affetti da leucemia acuta mieloide o linfoide all’esordio. L’approccio del silenziamento genico è stato utilizzato per determinare il ruolo che BAG-1 svolge principalmente nelle leucemie acute mieloidi (LAM), permettendoci di scoprire che l’indotta sotto-espressione di BAG-1 comporta una ridotta espressione di alcune proteine molto importanti per conferire un vantaggio proliferativo alle cellule tumorali. L’espressione di BAG-1 nelle cellule leucemiche è stata dimostrata essere inversamente proporzionale all’espressione di BAG-3, gene della stessa famiglia genica con funzione altamente simile a quella di BAG-1, e questo fenomeno di compensazione genica è stato dimostrato svolgere un ruolo di forte impatto sulla sopravivenza delle cellule leucemiche soprattutto se entrambi i geni venivano silenziati insieme. Un aumento della morte cellulare, confermata dopo il co-silenziamento di BAG-1;3 in linee leucemiche e in colture primarie di LAM è stata osservata, così come l’attivazione delle proteine caspasi-3 e PARP e il rilascio delle molecole pro-apoptotiche citocromo c e Smac/DIABLO. L’elemento chiave del co-silenziamento di BAG-1 e BAG-3 è stato individuato essere soprattutto a livello di repressione dell’espressione proteica di elementi anti-apoptotici, quali Bcl-2, Mcl-1 e Bcl-XL, così come di alcuni regolatori della proliferazione come ERK1/2 e ciclina D1. La nostra ipotesi è che BAG-1 possa rivestire un ruolo importante nella protezione della degradazione di alcune di queste proteine che normalmente vengono degradate via proteasoma. Infatti, dato che queste proteine risultavano diminuite dopo il silenzia mento transitorio di BAG-1;3, la mancanza di questi fattori noti per regolare il turnover proteico, dunque supportava il loro contributo alla aumentata degradazione proteica oservata. E’ molto probabile che il ruolo di BAG-1/-3 avvenga direttamente o indirettamente. Infatti, BAG-1 è noto interagire direttamente con particolari fattori, e noi abbiamo dimostrato che così avviene per Bcl-2, fenomeno già descritto in altri tessuti, e con una proteina di recente interesse la Usp9X, mai prima identificata tra i target diretti di BAG-1. L’abbassamento di BAG-1;3, molto probabilmente tramite Usp9X, ha influenzato l’espressione di Mcl-1, un altro fattore importante nell’apoptosi delle LAM, dimostrando che silenziamento era in grado di influenzare le cellule leucemiche provocando un blocco di induzione dell’apoptosi. Infine, BAG-1 e BAG-3 si candidano a nuove molecole con un potenziale ruolo nel mantenimento delle LAM. L’identificazione dei loro principali targets molecolari, quali Bcl-2, Mcl-1 e Usp9X, affetti particolarmente da BAG-1, portano novità sul ruolo di nuovi pathway che potrebbero essere considerati nelle LAM pediatriche e per futuri sviluppi di targets terapeutici.

There is an urgent need to develop crops that can withstand future climates. Results from this thesis demonstrated that a native Australian resurrection grass exhibits structural, physiological and metabolic strategies to tolerate drying. These strategies may be utilized for the generation of stress tolerant crops.

Proton therapy is an established radiotherapy technique for the treatment of complex cancers. However, problems exist in the planning of treatments where the use of inaccurate dose modelling may lead to treatments being delivered which are not optimal. Most of the problems with dose modelling tools used in proton therapy treatment planning lie in their treatment of processes such as multiple Coulomb scattering, therefore a technique that accurately models such effects is preferable. Monte Carlo simulation alleviates many of the problems in current dose models but, at present, well-validated full-physics Monte Carlo simulations require more time than is practical in clinical use. Using the well-known and well-validated Monte Carlo toolkit Geant4, an application-called PTMC-has been developed for the simulation of proton therapy treatment plans. Using PTMC, several techniques to improve throughput were developed and evaluated, including changes to the tracking algorithm in Geant4 and application of large scale parallelism using novel computing architectures such as the Intel Xeon Phi co-processor. In order to quantify any differences in the dose-distributions simulated when applying these changes, a new dose comparison tool was also developed which is more suited than current techniques for use with Monte Carlo simulated dose distributions. Using an implementation of the Woodcock algorithm developed in this work, it is possible to track protons through a water phantom up to eight times faster than using the PRESTA algorithm present in Geant4, with negligible loss of accuracy. When applied to a patient simulation, the Woodcock algorithm increases throughput by up to thirty percent, though step limitation was necessary to preserve simulation accuracy. Parallelism was implemented on an Intel Xeon Phi co-processor card, where PTMC was tested with up to 244 concurrent threads. Difficulties imposed by the limited RAM available were overcome through the modification of the Geant4 toolkit and through the use of a novel dose collation technique. Using a single Xeon Phi co-processor, it is possible to validate a proton therapy treatment plan in two hours; with two co-processors that simulation time is halved. For the treatment plan tested, two Xeon Phi co-processors were roughly equivalent to a single 48-core AMD Opteron machine. The relative costs of Xeon Phi co-processors and traditional machines have also been investigated; at present the Intel Xeon Phi co-processor is not cost competitive with standard hardware, costing around twice as much as an AMD machine with comparable performance. Distributed parallelism was also implemented through the use of the Google Compute Engine (GCE). A tool has been developed-called PYPE-which allows users to launch large clusters in the GCE to perform arbitrary compute-intensive work. PYPE was used with PTMC to perform rapid treatment plan validation in the GCE. Using a large cluster, it is possible to validate a proton therapy treatment plan in ten minutes at a cost of roughly $10; the same plan computed locally on a 24-thread Intel Xeon machine required five hours. As an example calculation using PYPE and PTMC, a robustness study is undertaken for a proton therapy treatment plan; this robustness study shows the usefulness of Monte Carlo when computing dose distributions for robustness studies, and the utility of the PYPE tool to make numerous full physics Monte Carlo simulations quickly. Using the tools developed in this work, a complete treatment plan robustness study can be performed in around 26 hours for a cost of less than $500, while using full-physics Monte Carlo for dose distribution calculations.

Plant biotechnology holds great promise to help meet the supply-demand gaps of agriculture to feed the future population. This thesis investigated the molecular mechanisms of stress tolerance conferred by the Arabidopsis thaliana Bcl-2 associated athanogene 4 (AtBAG4), cytoprotective protein. The research identified a role for AtBAG4 in several plant stress response pathways and further investigated the implications of expressing AtBAG4 in chickpeas. The AtBAG4-chickpea were equivalent to commercially available chickpea in non-stressed conditions but supported improved yields under drought. This knowledge will be used to develop improved chickpea varieties that tolerate stress without yield penalty.

The study of RNA-binding proteins has recently increased in importance due to discoveries of their larger role in cellular processes. One study currently conducted at Umeå University involves constructing a model that will be able to improve our knowledge about T-cells by explaining how these cells work in different diseases. But before this model can become a reality, Umeå Univerity needs to investigate the relation between RNA and RNA-binding proteins and find proteins of which highly contribute to the activity of the RNA-binding proteins. To do so, they have decided to use four penalized regression Machine Learning models to analyse protein sequences from CD4 cells. These models consist of a ridge penalized model, an elastic net model, a neural network model, and a Bayesian model. The results show that the models have a number of RNA-binding protein sequences in common which they list as highly decisive in their predictions.

Oxygen and nitric oxide reductases are enzymes found in aerobic and anaerobic respiration, respectively. Both enzyme groups belong to the superfamily of Heme-Copper Oxidases, which is further divided into several subgroups: oxygen-reducing enzymes into A-, B- and C-type and nitric oxide reductases into qNORs and cNORs. Oxygen reducing enzymes use the energy released from oxygen reduction to take up electrons and protons from different sides of the membrane. Additionally, protons are pumped. These processes produce a membrane potential, which is used by the ATP-synthase to produce ATP, the universal energy currency of the cell. Nitric oxide reductases are not known to conserve the energy from nitric oxide reduction, although the reaction is highly exergonic. Here, the detailed mechanism of a B-type oxidase is studied with special interest in an element involved in proton pumping (proton loading site, PLS). The study supports the hypothesis that the PLS is protonated in one and deprotonated in the consecutive step of the oxidative catalytic cycle, and that a proton is pumped during the final oxidation phase. It further strengthens the previous suggestion that the PLS is a cluster instead of a single residue or heme propionate. Additionally, it is proposed that the residue Asp372, which is in vicinity of the heme a3 propionates previously suggested as PLS, is part of this cluster. In another study, we show that the Glu15II at the entry of the proton pathway in the B-type oxidase is the only crucial residue for proton uptake, while Tyr248 is or is close to the internal proton donor responsible for coupling proton pumping to oxygen reduction. The thesis also includes studies on the mechanism and electrogenicity of qNOR. We show that there is a difference in the proton-uptake reaction between qNOR and the non-electrogenic homolog cNOR, hinting at a different reaction mechanism. Further, studies on a qNOR from a different host showed that qNOR is indeed electrogenic. This surprising result opens up new discussions on the evolution of oxygen and nitric oxide reductases, and about how energy conservation can be achieved.<br><p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

HSP70 plays an important role in cancer development. However, the molecular role of HSP70 in cancer is poorly understood. Previous work from our laboratory demonstrated that HSP70 is essential for initiation of Her2-positive breast cancer by controlling oncogene-induced senescence. Here we demonstrate that HSP70 is critical for both initiation and progression of mammary cancer. Interestingly, the role of HSP70 in cancer development did not involve its canonical function as a molecular chaperone. Instead, HSP70 had multiple effects on signaling pathway components related to tumor initiation, growth, and metastasis, such as FOXM1, HIF1, NF-𝜅B, and SRC. HSP70 regulated signaling networks via association with the co-chaperone, BAG3, a scaffold protein with capacity to interact with multiple key regulators of cell signaling. Using SRC as a model, we demonstrated that association with HSP70 attenuates BAG3's interaction with the SH3 domain of SRC. We also show that an HSP70-interacting small molecule, YM-1, can specifically inhibit the HSP70-BAG3 signaling axis, leading to selective inhibition of tumor growth in vivo and in vitro. This compound mimicked the effects seen with depletion of HSP70 in a dose dependent manner, providing a proof of principle that the association of HSP70 and BAG3 is needed for regulation of these pathways. Additionally, a second generation of YM-1 analogs, JG-98 and JG-84, were shown to be more potent than YM-1 while acting in a similar fashion on signaling pathways. A less potent analog, JG-36, was not able to modulate these pathways as effectively. These studies demonstrate that the HSP70-BAG3 axis is a major regulator of cancer signaling and suggest that targeting the interface between HSP70 and BAG3 is a novel therapeutic approach.

Aging remains to this day one of the unresolved biology areas of upmost importance and many age-related diseases are on the rise worldwide. One of aging major hallmarks, proteostasis, has several associated pathways across different segments which have not yet been fully detailed in various cell lines and are needed to better understand the underlying aging problem. Here, using a neuronal-like cell line such as SH-SY5Y, several ER stress biomarkers and proteostasis associated targets are evaluated under ER stress-induced environment through tunicamycin (TUN) or thapsigargin (TG) presence. The inclusion of neuroprotective agents such as TUDCA and homegrown compounds (HA compounds) were also included to better evaluate successful chemical reversion of ER stress and protein aggregation through target proteins. BAG3, ATF4, Calreticulin and pERK1/2 were some of the proteins included in this report as biomarkers for ER stress induction using protein or gene expression level analysis. ER stress was effectively induced with thapsigargin or tunicamycin across all target proteins. ATF4, calreticulin and pERK1/2 protein and/or gene expression values decreased after neuroprotective agents’ treatment. However, no ER stress reversion was achieved for GRP78 and BAG3. XBP1s achieved positive results only for tunicamycin-treated conditions. Overall, ER stress induction was partially or totally reverted with success by TUDCA and HA compounds in SH-SY5Y.<br>O envelhecimento permanece até hoje uma das áreas biológicas por resolver de maior importância. Muitas doenças associadas ao envelhecimento estão a aumentar de forma global. Uma característica principal associada ao envelhecimento é a proteostase, cujos diferentes componentes ainda não foram totalmente descritos em diferentes linhas celulares. Aqui, usando um modelo celular neuronal como as células SH-SY5Y, diversos biomarcadores de stress do retículo endoplasmático e de agregação proteica foram avaliados em ambientes de stress do RE induzidos por tunicamicina ou tapsigargina, bem como a sua reversão. A inclusão de agentes protetores (TUDCA) e reversores químicos da agregação proteica (compostos HA) foram incluídos para melhor avaliar essa mesma reversão do stress do RE. BAG3, ATF4, calreticulina e pERK1/2 foram algumas das proteínas incluídas nesta dissertação e a avaliação do stress do RE foi alcançada pela análise dos seus níveis de expressão proteicos e/ou génicos. A indução do stress do RE foi alcançada eficazmente tanto para a tapsigargina como para a tunicamicina, em todas as proteínas-alvo, nesta linha celular. ATF4, calreticulina e pERK1/2 foram diminuídas pela ação dos agentes protetores e, consequentemente, diminuiu o stress do RE. No entanto, para a GRP78 e BAG3, não se obtiveram resultados de reversão do stress do RE. XBP1s apenas alcançou resultados significativos de reversão no caso das condições tratadas com tunicamicina. Em suma, o stress do RE induzido por TG ou TUN foram revertidos parcialmente ou na sua totalidade com sucesso pelos agentes protetores nesta linha celular.<br>Mestrado em Biomedicina Molecular

Yes<br>Rpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13. Hence, overexpression of the SGTA-binding region of Rpn13 or point mutations within the SGTA TPR domain both inhibit SGTA binding to the proteasome and substantially reduce MLP levels. These findings suggest that SGTA can regulate the access of MLPs to the proteolytic core of the proteasome, implying that a protein quality control cycle that involves SGTA and the BAG6 complex can operate at the 19S regulatory particle. We speculate that the binding of SGTA to Rpn13 enables specific polypeptides to escape proteasomal degradation and/or selectively modulates substrate degradation.<br>BBSRC [grant number: BB/L006510/1] and the Wellcome Trust [grant number: 092107/Z/10/Z]. K.K. was supported by the UPStream network [EU, FP7, ITN project 290257]

碩士<br>元智大學<br>資訊工程學系<br>106<br>Deep learning, a subset of AI and machine learning, uses multi-layered artificial neural networks to deliver state-of-the-art performance in tasks such as object detection, speech recognition, language translation and so on. In bioinformatics, Deep learning also has been applied to transform biomedical data into valuable knowledge since the early 2000s and demonstrated remarkable scientific achievements nowadays. As a result, it not only shortens the study time but also produces more accurate and reliable results. In this study, I propose a novel approach for extracting hidden information on the amino acid sequence in the primary protein structure using word embedding which has applied successfully in the natural language researches. Unlike conventional language models, the primary protein structure which resembles an unknown language with 20 words corresponding to 20 amino acids. An ordered chain of words may itself contain the information of biological functions which make a significant contribution to the classification of proteins. This study is attempted to perform directly from the FASTA format of amino acid sequences. I choose electron transport proteins, a bunch of proteins that transfer electrons in metabolic processes for cellular function, to implement this work. Therefore, the study of the identification and classification of electron transport proteins will contribute significantly to improving the understanding of the transport protein process and their roles in energy production in cells. Facebook Fasttext used as a modeling tool which implements the hashing trick for a fast and memory efficient mapping to perform this study. The result of successfully identifying electron transport proteins in transport proteins archived sensitivity of 60.53%, specificity of 94.84%, and accuracy of 91.71%, with MCC of 0.53 for independent testing. This method also improves the measurement metrics compared to previous related works. The proposed technique provides a web-based online tool for research purposes and also opens up promises for implementing natural language methods to solve problems in this field.

碩士<br>國立陽明大學<br>口腔生物研究所<br>103<br>Oral squamous cell carcinoma (OSCC) is a major subtype of head and neck squamous cell carcinoma (HNSCC). Depanding on the data, OSCC mortality rate is increasing year by year. Tid1, a DnaJ cochaperon protein, can bind with HSP70, functions as a tumour suppressor in OSCC tumourigenesis. We previously used systemic proteomics analysis to identify Tid1 interacting protein. The HPD loop of DnaJ domain could bind with HSP70 which on Tid1 was mutated by site-directed mutagenesis. Through affinity chromatography and mass spectrometry we identified BAG2 that specifically interact with Tid1 short form (Tid1-S) lacking the functional DnaJ domain. However, the role of BAG2 in OSCC tumourigenesis remains unclear. First, co-immunoprecipitation analysis and confocal microscope were performed to confirm the protein interaction between BAG2 and Tid1. Besides, BAG2 and Tid1 are colocolization in mitochondrial. No matter overexpression or silencing BAG2 in OSCC cells, it always has effects on their phenotypes. Together, these findings suggest that, Tid1 and BAG2 have important roles in OSCC cells.

Yes<br>Protein quality control mechanisms are essential for cell health and involve delivery of proteins to specific cellular compartments for recycling or degradation. In particular, stray hydrophobic proteins are captured in the aqueous cytosol by a co-chaperone, the small glutamine-rich, tetratricopeptide repeat-containing protein alpha (SGTA), which facilitates the correct targeting of tail-anchored membrane proteins, as well as the sorting of membrane and secretory proteins that mislocalize to the cytosol and endoplasmic reticulum-associated degradation. Full-length SGTA has an unusual elongated dimeric structure that has, until now, evaded detailed structural analysis. The Cterminal region of SGTA plays a key role in binding a broad range of hydrophobic substrates, yet in contrast to the well-characterized N-terminal and TPR domains, there is a lack of structural information on the C-terminal domain. In this study, we present new insights into the conformation and organization of distinct domains of SGTA and show that the C-terminal domain possesses a conserved region essential for substrate processing in vivo. We show that the C-terminal domain region is characterized by α-helical propensity and an intrinsic ability to dimerize independently of the N-terminal domain. Based on the properties of different regions of SGTA that are revealed using cell biology, NMR, SAXS, Native MS, and EPR, we observe that its C-terminal domain can dimerize in the full-length protein and propose that this reflects a closed conformation of the substrate-binding domain. Our results provide novel insights into the structural complexity of SGTA and provide a new basis for mechanistic studies of substrate binding and release at the C-terminal region.<br>MRC New Investigator Research Grant: G0900936; BBSRC grants: BB/L006952/1 and BB/L006510/1; BBSRC grant: BB/N006267/1; Wellcome Trust Investigator Award in Science: 204957/Z/16/Z; BBSRC grant: BB/J014567/1