Journal of Biological Chemistry最新文献

{"title":"Phosphorylation-mediated Regulation of the NADPH-dependent Glutamate Dehydrogenase, SpGdh1, from Schizosaccharomyces pombe.","authors":"Yi-Fan Wang, Takeo Tomita, Ayako Yoshida, Saori Kosono, Makoto Nishiyama","doi":"10.1016/j.jbc.2025.110422","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110422","url":null,"abstract":"<p><p>Glutamate dehydrogenase from the yeast Schizosaccharomyces pombe (SpGdh1) is a pivotal enzyme that catalyzes the conversion of 2-oxoglutarate and ammonium to glutamate using NADPH as a coenzyme. Although SpGdh1 is phosphorylated at several residues, the impact of phosphorylation on enzyme activity and the underlying molecular mechanisms remain unclear. To elucidate the phosphorylation-mediated regulation of SpGdh1, we determined the crystal structure of SpGdh1 binding 2-iminoglutarate (2-IG) and NADP⁺. The results of the structural analysis revealed that four serine residues for phosphorylation were located near the active site. Ser252 directly interacted with the 2'-phosphate group of the adenine ribose moiety of NADP⁺, suggesting that the phosphorylation of Ser252 interfered with NADP⁺ binding. To confirm this hypothesis, we prepared SpGdh1 phosphorylation-mimic (Ser to Glu) variants of SpGdh1 at these four Ser residues. The results of a kinetic analysis revealed that the replacement of these four residues increased the apparent K_m^NADP(H) value and decreased catalytic efficiency, k_cat/K_m^NADP(H).In contrast, substitutions decreased the apparent K_m^NAD(H) value and increased catalytic efficiency, k_cat/K_m^NAD(H). Therefore, the Ser to Glu replacement caused net shifts in the coenzyme specificities (NADPH to NADH and NADP⁺ to NAD⁺) of 55- and 2900-fold, respectively. This is the first study to reveal the effects of the phosphorylation of SpGdh1 on its activity.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110422"},"PeriodicalIF":4.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144512013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cathepsin K as a key regulator of myocardial fibrosis in dilated cardiomyopathy and a promising therapeutic target.","authors":"Lanlan Ma, Bingjun Lu, Yueqiao Si, Lingyan Dai, Mingyue Tan, Wujian Liu, Dongdong Sun, Jiangcheng Shu, Cong Chen, Qi Xiang, Dingsheng Jiang, Xiang Wei, Wei Eric Wang","doi":"10.1016/j.jbc.2025.110421","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110421","url":null,"abstract":"<p><p>Dilated cardiomyopathy (DCM) is a leading cause of heart failure with a high mortality rate. Cardiac fibrosis plays a critical role in the progression of DCM, yet therapeutic strategies targeting fibrosis remain limited. Therefore, it is essential to investigate the underlying mechanisms of fibrosis in DCM. Our study demonstrates through the integration of weighted gene co-expression network analysis and gene ontology annotation that 35 biological processes, including cytokine production, were significantly associated with fibrosis in DCM. Protein-protein interaction analysis identified 82 crucial genes. The scRNA-seq identified Cathepsin K (CTSK) as primarily expressed in cardiac fibroblasts. Masson's trichrome and immunofluorescence staining revealed that the level of fibrotic tissue in the left ventricle of patients with DCM and the expression of CTSK are higher than those in the normal ventricle. In vitro studies demonstrated that CTSK expression was upregulated in highly proliferative human cardiac fibroblasts (HCFs). PDGF-BB stimulation notably promoted HCF proliferation, an effect that was significantly attenuated by CTSK knockdown. However, CTSK depletion showed no inhibitory impact on TGF-β1-induced transdifferentiation of cardiac fibroblasts into myofibroblasts. Our research indicates that CTSK is a key regulator of myocardial fibrosis in DCM and is a promising therapeutic target.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110421"},"PeriodicalIF":4.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144512011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An anti-CD47 antibody binds to a distinct epitope in a novel metal ion-dependent manner to minimize cross-linking of red blood cells.","authors":"Xiao Lu, Ziyue Chen, Chunyan Yi, Zhiyang Ling, Jing Ye, Kaijian Chen, Yao Cong, Sonam Wangmo, Shipeng Cheng, Ran Wang, Danyan Zhang, Jiefang Xu, Jichao Yang, Liyan Ma, Qing Duan, Xiaoyu Sun, Jianping Ding, Bing Sun","doi":"10.1016/j.jbc.2025.110420","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110420","url":null,"abstract":"<p><p>Cluster of differentiation 47 (CD47) is a widely expressed transmembrane protein that plays a crucial role in immune self-recognition. Cancer cells upregulate CD47 expression to promote immune escape through activating the \"don't eat me\" signal via interactions with signal regulatory protein α (SIRPα) on macrophages. The effectiveness of anti-CD47 antibodies has been demonstrated in multiple tumour models. However, since CD47 is also expressed in human red blood cells (RBCs) and platelets, the clinical application of anti-CD47 antibodies requires careful consideration of blood toxicity. One major obstacle to the clinical application of CD47 antibodies is the haemagglutination caused by RBCs cross-linking. In this study, we generated Hu1C8, a humanized anti-CD47 monoclonal antibody that demonstrated increased selectivity for binding to CD47 on cancer cells and lacked haemagglutination activity. Epitope mapping and the crystal structure of the Hu1C8 Fab-CD47 extracellular domain (ECD) complex revealed that Hu1C8 binds to a distinct epitope of CD47 in a Ca²⁺-dependent manner. The unique recognition and binding mode allowed Hu1C8 to bind CD47 on RBCs with reduced haemagglutination activity while still maintaining effective antitumour activity. These findings demonstrate a feasible strategy for developing CD47 antibodies with high antitumor activity but low RBC haemagglutination activity. Our study elucidates how epitope-specific antibody influences antibody-induced cell cross-linking, offering innovative strategies for antibody design to either leverage or avoid cell cross-linking effects.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110420"},"PeriodicalIF":4.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144512010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Poly(A) Polymerase Star-PAP is Regulated by Stably Associated Phosphoinositide Messengers.","authors":"Tianmu Wen, Mo Chen, Vincent L Cryns, Richard A Anderson","doi":"10.1016/j.jbc.2025.110412","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110412","url":null,"abstract":"<p><p>Star-PAP is a noncanonical poly(A) polymerase that controls gene expression. Star-PAP was previously reported to bind PIPKI⍺ and its product PI(4,5)P₂, which regulate Star-PAP activity and expression of specific genes. Recent studies have revealed a nuclear p53-phosphoinositide signaling pathway in which the phosphatidylinositol (PI) transfer proteins (PITPs) and phosphoinositide kinases/phosphatases bind p53 to sequentially modify p53-linked phosphoinositides and regulate p53 function. Here we demonstrate that multiple phosphoinositides are also coupled to Star-PAP in response to stress. This pathway is initiated by PITP⍺/β binding to Star-PAP, and the Star-PAP-phosphoinositide complexes are sequentially modified by PI4KII⍺, PIPKI⍺, IPMK, and PTEN. The formation of Star-PAP-phosphoinositide complexes enhances the association of the small heat shock proteins HSP27 and ⍺B-crystallin with Star-PAP. Knockdown of the PITPs, PIP kinases, or HSP27 reduces the expression of Star-PAP targets. Our results demonstrate that PITP⍺/β play a key role in the assembly of Star-PAP-phosphoinositide complexes that are sequentially interconverted by PIP kinases/phosphatases and recruit the small heat shock proteins to these complexes to regulate Star-PAP activity in response to stress.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110412"},"PeriodicalIF":4.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional investigation of the RNA helicase MOV10 with respect to its interplay with factors involved in nonsense-mediated mRNA decay.","authors":"Guangpu Xue,Gabriel P Faber,Lea S Pommerening,Megha Mallick,Aditi Gupta,Markus C Wahl,Yaron Shav-Tal,Sutapa Chakrabarti","doi":"10.1016/j.jbc.2025.110418","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110418","url":null,"abstract":"The RNA helicase Moloney leukemia virus 10 (MOV10) is involved in several RNA processing pathways, including RNA silencing, defence against viral RNA and nonsense-mediated mRNA decay (NMD). MOV10 is a member of the UPF1-family of superfamily 1 (SF1) helicases and like its prototype member, unwinds RNA duplexes bearing a 5'-single-stranded overhang. Sequence comparisons of MOV10 and UPF1 revealed significant identity between their RecA domains and considerable divergence between the N-terminal domains preceding the helicase core. Using an in vitro biochemical approach, we show that the N-terminal domain (NTD) of MOV10 is functionally distinct from the CH domain of UPF1, both in terms of its impact on catalytic activity and the protein-protein interactions it mediates. MOV10 engages the NMD factor UPF2 via its N-terminal regulatory domain but binds a different region than the UPF1-CH domain. We propose that the interactions mediated by the MOV10-NTD dictate its localization to cytoplasmic RNA condensates such as P-bodies and stress granules. This is distinct from UPF1, whose localization appears to be driven by its interaction with RNA. Taken together, our work presents a mechanistic model for the recruitment and involvement of MOV10 in NMD, where it was proposed to act as an RNA clearance factor for UPF1.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"187 1","pages":"110418"},"PeriodicalIF":4.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144504550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional investigation of the RNA helicase MOV10 with respect to its interplay with factors involved in nonsense-mediated mRNA decay.","authors":"Guangpu Xue, Gabriel P Faber, Lea S Pommerening, Megha Mallick, Aditi Gupta, Markus C Wahl, Yaron Shav-Tal, Sutapa Chakrabarti","doi":"10.1016/j.jbc.2025.110418","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110418","url":null,"abstract":"<p><p>The RNA helicase Moloney leukemia virus 10 (MOV10) is involved in several RNA processing pathways, including RNA silencing, defence against viral RNA and nonsense-mediated mRNA decay (NMD). MOV10 is a member of the UPF1-family of superfamily 1 (SF1) helicases and like its prototype member, unwinds RNA duplexes bearing a 5'-single-stranded overhang. Sequence comparisons of MOV10 and UPF1 revealed significant identity between their RecA domains and considerable divergence between the N-terminal domains preceding the helicase core. Using an in vitro biochemical approach, we show that the N-terminal domain (NTD) of MOV10 is functionally distinct from the CH domain of UPF1, both in terms of its impact on catalytic activity and the protein-protein interactions it mediates. MOV10 engages the NMD factor UPF2 via its N-terminal regulatory domain but binds a different region than the UPF1-CH domain. We propose that the interactions mediated by the MOV10-NTD dictate its localization to cytoplasmic RNA condensates such as P-bodies and stress granules. This is distinct from UPF1, whose localization appears to be driven by its interaction with RNA. Taken together, our work presents a mechanistic model for the recruitment and involvement of MOV10 in NMD, where it was proposed to act as an RNA clearance factor for UPF1.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110418"},"PeriodicalIF":4.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Choreography of E1 Enzymes in Ubiquitin-like Protein Cascades: New Insights into Dynamics and Specificity.","authors":"Caleb M Stratton, Pirouz Ebadi, Shaun K Olsen","doi":"10.1016/j.jbc.2025.110415","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110415","url":null,"abstract":"<p><p>In 2004, Aaron Ciechanover, Avram Hershko, and Irwin Rose were awarded the Nobel Prize in Chemistry for their groundbreaking work uncovering the stepwise, ATP-dependent degradation of cellular proteins. These studies laid the foundation for understanding ubiquitin (Ub) and ubiquitin-like (Ubl) proteins, an evolutionary conserved family of modifiers that mediate diverse cellular processes. The Ub/Ubl system operates through a reaction cascade involving E1 activating, E2 conjugating, and E3 ligating enzymes. As the initiating enzymes, E1s catalyze Ubl adenylation, thiolation, and thioester transfer to their cognate E2s. Despite their conserved architecture, E1s exhibit strict specificity for different Ubls and E2s, a critical feature for maintaining cellular homeostasis. While the molecular mechanisms underlying E1 interactions and activities remain incompletely understood, structural studies have provided key insights into the dynamic changes that accompany Ubl activation and transfer. This review highlights recent structures that build upon foundational biochemical research, elucidating the determinants of activity, specificity, and novel regulatory mechanisms governing E1 enzymes. We examine how conformational changes drive the transition from an adenylate-competent to a thioester-competent state and how these rearrangements facilitate interactions with Ubls and E2s while advancing the reaction cycle. Additionally, we explore recent insights into a prokaryotic E1-E2-like fusion that is structurally homologous to the noncanonical eukaryotic E1 ATG7, revealing its role in activating and conjugating a non-Ubl substrate and its implications for the evolutionarily trajectory of Ubl cascades. Finally, we discuss the current landscape of E1 inhibitors under investigation as potential anti-cancer therapies, as well as prospects for future investigations.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110415"},"PeriodicalIF":4.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal fluctuations in fluorescence intensity of rhodamine phalloidin-labeled actin filaments.","authors":"Kenta Toshino, Yosuke Yamazaki, Shunsuke Ando, Ryuichi Kaneda, Kazunori Ono, Takahiro Suzuki, Saku T Kijima, Taro Q P Uyeda","doi":"10.1016/j.jbc.2025.110417","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110417","url":null,"abstract":"<p><p>Phalloidin is widely used for fluorescent labeling of actin filaments. We observed ADP-actin filaments labeled with rhodamine-phalloidin or Alexa488-phalloidin in vitro and discovered that the fluorescence intensities along the filaments showed a mottled pattern of bright and dark regions. Filaments labeled with sub-stoichiometric rhodamine-phalloidin exhibited more significant fluorescence inhomogeneities than those labeled with excess rhodamine-phalloidin. Because the quantum yield of Alexa488 fluorescence is hardly affected by the environment, we concluded that the inhomogeneities arise from non-uniform phalloidin binding density rather than locally inhomogeneous quantum yield of the fluorophores. Simulations assuming random rhodamine-phalloidin binding alone partially produced fluorescence inhomogeneities, but the degree of inhomogeneities was significantly smaller than the experimental results. Furthermore, filaments co-labeled with rhodamine-phalloidin and Alexa488-phalloidin showed a positive correlation in fluorescence intensities of rhodamine and Alexa488. Moreover, addition of Pi suppressed the fluorescence inhomogeneities and the correlation between the rhodamine and Alexa488 fluorescence intensities. These results indicated that two mechanisms contribute to the non-uniform binding density of phalloidin: (i) stochastic binding and (ii) local differences in phalloidin binding affinity caused by Pi-sensitive structural polymorphism of actin filaments. This structural polymorphism may also affect the binding of various actin-binding proteins, contributing to the functional differentiation of actin filaments in vivo. Moreover, those mottled fluorescence patterns dynamically fluctuated over time. These temporal fluorescence fluctuations required glucose and glucose oxidase but were suppressed by Trolox, likely reflecting photophysical properties of fluorophores influenced by oxygen scavengers and triplet-state quenchers. Taken together, we provide new insights into the structural polymorphism of actin filaments.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110417"},"PeriodicalIF":4.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microcurrent stimulation induces cell death in p53-mutant and 5-FU-resistant breast cancer.","authors":"Tomohito Tanihara, Yuya Yoshida, Takashi Ogino, Yuma Terada, Fumiaki Tsurusaki, Keika Hamasaki, Kaita Otsuki, Kohei Fukuoka, Kosuke Oyama, Akito Tsuruta, Kengo Hamamura, Kouta Mayanagi, Satoru Koyanagi, Yuichi Murakami, Mayumi Ono, Michihiko Kuwano, Shigehiro Ohdo, Naoya Matsunaga","doi":"10.1016/j.jbc.2025.110414","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110414","url":null,"abstract":"<p><p>5-Fluorouracil (5-FU) is a commonly used chemotherapeutic agent for breast cancer. Its efficacy relies on the function of p53, and mutations in p53 contribute to the development of resistance during 5-FU chemotherapy. Here, we report that microcurrent stimulation (MCS) of a p53-mutant breast cancer cell line induces p53-mediated cell death. Although MDA-MB-231 and MDA-MB-468 cells, both human breast cancer cell lines, are less sensitive to 5-FU due to p53 mutations, MCS (300 μA for 30 min) induced apoptosis in these cells and improved the antitumor effect of 5-FU in tumor-bearing mice. MCS-induced apoptosis was mediated by an increase in intracellular Cu²⁺ ions and reactive oxygen species, along with the concurrent transcriptional enhancement of pro-apoptotic genes by p53. Furthermore, MCS induced apoptosis in MDA-MB-231 cells that had developed resistance to 5-FU and inhibited tumor growth in tumor-bearing mice with reduced 5-FU sensitivity. These findings suggest that an approach involving MCS could serve as a foundation for developing breast cancer treatment strategies to overcome p53 mutations.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110414"},"PeriodicalIF":4.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144505806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A molecular basis underpinning TRBV28+ T cell receptor recognition of MR1-antigen.","authors":"Wael Awad,Nicholas A Gherardin,Lisa Ciacchi,Andrew N Keller,Ligong Liu,David P Fairlie,James McCluskey,Dale I Godfrey,Jamie Rossjohn","doi":"10.1016/j.jbc.2025.110416","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110416","url":null,"abstract":"Mucosal-associated invariant T (MAIT) cells express a TRAV1-2+ T cell receptor (TCR) that recognises microbial vitamin B2-derivatives presented by the MHC class I-related molecule, MR1. Most MAIT TCRs incorporate a biased TCR-β repertoire, predominantly TRBV20-1 and TRBV6, but some utilise other TRBV genes, including TRBV28. A second conserved, albeit less frequent TRAV36+ TRBV28+ T cell population exhibits MAIT-like phenotypic features but use a markedly distinct mode of MR1-antigen-recognition compared to MAIT TCR-MR1 binding. Nevertheless, our understanding of how differing TCR gene usage results in altered MR1 binding modes remains incomplete. Here, binding studies demonstrated differential affinities and antigen-specificities between TRBV6+ and TRBV28+ MR1-restricted TCRs. Alanine-scanning mutagenesis on the TRAV36-TRBV28 TCR, revealed a strong dependence on germline-encoded residues within the highly selected CDR3α loop, similar to TRAV1-2- TRBV6 TCRs, and further alanine-scanning mutagenesis experiments demonstrate differential energetic footprints by these TCRs atop MR1. We determined the crystal structure of a MAIT TRAV1-2-TRBV28+ TCR-MR1-5-OP-RU ternary complex. This structure revealed a docking mode conserved amongst other TRAV1-2+ MAIT TCRs, with the TRBV28-encoded TCR-β chain adopting highly distinct docking modes between the TRAV1-2+ and TRAV36+ TCRs. This indicates that the TCR-α chain dictates the positioning and role of the TCR-β chain. Taken together, these findings provide new molecular insights into MR1-Ag driven selection of paired TCR-α and TCR-β chains.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"36 1","pages":"110416"},"PeriodicalIF":4.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144504549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}