Journal of Biological Chemistry最新文献_第5页

A new age in structural S-layer biology - Experimental and in silico milestones. 结构s层生物学的新时代-实验和硅里程碑。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-07 DOI: 10.1016/j.jbc.2025.110205

Stephanie Grill-Walcher,Christina Schäffer

{"title":"A new age in structural S-layer biology - Experimental and in silico milestones.","authors":"Stephanie Grill-Walcher,Christina Schäffer","doi":"10.1016/j.jbc.2025.110205","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110205","url":null,"abstract":"Surface (S-) layer proteins, considered as the most abundant proteins in nature, perform diverse and essential biological roles in many bacteria and most archaea. Their functions range from providing structural support, maintaining cell shape, and protecting against extreme environments to acting as a cell surface display matrix for biologically active molecules, such as S-layer protein-bound glycans, which facilitate interspecies interactions and cellular communication in both health and disease. The intricate, symmetric, nanometer-scale patterns of S-layer lattices have long fascinated structural biologists, yet only recent methodological advances have revealed detailed molecular insights. These advances include a deeper understanding of domain organization, cell wall anchoring mechanisms, and how nascent proteins are incorporated into existing lattices. Significant progress in sample preparation and high-resolution imaging has led to the precise structural characterization of S-layers across various bacterial and archaeal species. Furthermore, the advent of deep learning-based structure prediction has enabled modeling of S-layer proteins in several largely uncultured microbial lineages. This review summarizes major achievements in S-layer protein structural research over the past five years, presenting them with a typical workflow for the experimental structure determination. For the first time, it also explores recent breakthroughs in computational S-layer modelling and offers an outlook on how in silico methods may further advance our understanding of S-layer protein architecture.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"19 1","pages":"110205"},"PeriodicalIF":4.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932537","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}

引用次数: 0

Setdb1 and Atf7IP form a hetero-trimeric complex that blocks Setdb1 nuclear export. Setdb1和Atf7IP形成异三聚体复合物，阻断Setdb1核输出。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-06 DOI: 10.1016/j.jbc.2025.110171

Leena Kariapper, Ila A Marathe, Ashley Brower Niesman, Kelly Suino-Powell, Yuh Min Chook, Vicki H Wysocki, Evan J Worden

{"title":"Setdb1 and Atf7IP form a hetero-trimeric complex that blocks Setdb1 nuclear export.","authors":"Leena Kariapper, Ila A Marathe, Ashley Brower Niesman, Kelly Suino-Powell, Yuh Min Chook, Vicki H Wysocki, Evan J Worden","doi":"10.1016/j.jbc.2025.110171","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110171","url":null,"abstract":"Histone H3K9 methylation (H3K9me) by Setdb1 silences retrotransposons (rTE) by sequestering them in heterochromatin. Atf7IP is a constitutive binding partner of Setdb1 and is responsible for Setdb1 nuclear localization, activation and chromatin recruitment. However, structural details of the Setdb1/Atf7IP interaction have not been elucidated. We used Alphafold2 predictions and biochemical reconstitutions to show that one copy of Setdb1 and two copies of Atf7IP form a hetero-trimeric complex in vitro and in cells. We also find that Atf7IP self-associates, forming multimeric complexes that are resolved upon Setdb1 binding. Setdb1 binds to Atf7IP through coiled coil interactions that include both Setdb1 nuclear export signals (NES). Atf7IP directly competes with CRM1 to bind the Setdb1 NES motifs, explaining how Atf7IP prevents CRM1-mediated nuclear export of Setdb1. Setdb1 also forms hetero-trimeric complexes with the Atf7IP paralog Atf7IP2 and we show that Setdb1 can form mixed heterotrimers comprising one copy of each Setdb1, Atf7IP and Atf7IP2. Atf7IP and Atf7IP2 are co-expressed in many tissues suggesting that heterotrimers with different compositions of Atf7IP and Atf7IP2 may differentially regulate H3K9me by fine-tuning Setdb1 localization and activity.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110171"},"PeriodicalIF":4.0,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144025496","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}

引用次数: 0

Cellular crosstalk in fibrosis: insights into macrophage and fibroblast dynamics. 纤维化中的细胞串扰：巨噬细胞和成纤维细胞动力学的见解。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-05 DOI: 10.1016/j.jbc.2025.110203

Zachary S C S Froom,Neal I Callaghan,Locke Davenport Huyer

{"title":"Cellular crosstalk in fibrosis: insights into macrophage and fibroblast dynamics.","authors":"Zachary S C S Froom,Neal I Callaghan,Locke Davenport Huyer","doi":"10.1016/j.jbc.2025.110203","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110203","url":null,"abstract":"Pathological fibrosis, the excessive deposition of extracellular matrix and tissue stiffening that causes progressive organ dysfunction, underlies diverse chronic diseases. The fibrotic microenvironment is driven by the dynamic microenvironmental interaction between various cell types; macrophages and fibroblasts play central roles in fibrotic disease initiation, maintenance, and progression. Macrophage functional plasticity to microenvironmental stimuli modulates fibroblast functionality by releasing pro-inflammatory cytokines, growth factors, and matrix remodeling enzymes that promote fibroblast proliferation, activation, and differentiation into myofibroblasts. Activated fibroblasts and myofibroblasts serve as the fibrotic effector cells, secreting extracellular matrix components and initiating microenvironmental contracture. Fibroblasts also modulate macrophage function through the release of their own pro-inflammatory cytokines and growth factors, creating bidirectional crosstalk that reinforces the chronic fibrotic cycle. The intricate interplay between macrophages and fibroblasts, including their secretomes and signaling interactions, leads to tissue damage and pathological loss of tissue function. In this review, we examine macrophage-fibroblast reciprocal dynamic interactions in pathological fibrotic conditions. We discuss the specific lineages and functionality of macrophages and fibroblasts implicated in fibrotic progression, with focus on their signal transduction pathways and secretory signalling that enables their pro-fibrotic behaviour. We then finish with a set of recommendations for future experimentation with the goal of developing a set of potential targets for anti-fibrotic therapeutic candidates. Understanding the cellular interactions between macrophages and fibroblasts provides valuable insights into potential therapeutic strategies to mitigate fibrotic disease progression.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"58 1","pages":"110203"},"PeriodicalIF":4.8,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921068","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}

引用次数: 0

TOX High Mobility Group Box Family Member 4 Promotes DNA Double Strand Break Repair via Non-Homologous End Joining. TOX高迁移率组盒家族成员4通过非同源末端连接促进DNA双链断裂修复。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-04 DOI: 10.1016/j.jbc.2025.110174

Feifei Wang,Wenli Gui,Mengtao Rong,Liang Zhang,Jiajing Wu,Juan Li,Renqing Wang,Odjo G Gouttia,Ling Wang,Xingyuan Yang,Aimin Peng

{"title":"TOX High Mobility Group Box Family Member 4 Promotes DNA Double Strand Break Repair via Non-Homologous End Joining.","authors":"Feifei Wang,Wenli Gui,Mengtao Rong,Liang Zhang,Jiajing Wu,Juan Li,Renqing Wang,Odjo G Gouttia,Ling Wang,Xingyuan Yang,Aimin Peng","doi":"10.1016/j.jbc.2025.110174","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110174","url":null,"abstract":"Non-homologous end joining (NHEJ) is a pivotal mechanism in the repair of DNA double-strand breaks (DSBs). Central to NHEJ is the DNA-dependent protein kinase (DNA-PK) complex, comprising the KU heterodimer and the catalytic subunit, DNA-PKcs. In this study, we characterize TOX High Mobility Group Box Family Member 4 (TOX4) as a factor recruited to both laser-induced DNA damage and endonuclease-induced DNA DSBs. Depletion of TOX4 leads to accumulation of DNA damage, which is epistatic to DNA-PKcs. Consistently, TOX4 depletion substantially reduces NHEJ efficiency measured using both intrachromosomal and extrachromosomal repair assays. Our proteomic and biochemical analyses reveal TOX4 association with DNA-PK that is required for DNA-PKcs activation. Furthermore, we show that TOX4 coordinates with Phosphatase 1 Nuclear-Targeting Subunit (PNUTS) in NHEJ. PNUTS, previously shown to protect DNA-PKcs phosphorylation from protein phosphatase 1 (PP1)-mediated dephosphorylation, binds DNA-PK in a TOX4-dependent manner. In line with its role in DNA repair, TOX4 emerges as a promising target for anti-cancer drug development, and its targeting enhances tumor cell sensitivity to DNA damage in head and neck cancer and other malignancies.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"56 1","pages":"110174"},"PeriodicalIF":4.8,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915234","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}

引用次数: 0

The Nucleocapsid protein of Crimean Congo hemorrhagic fever virus interacts with eIF4A to promote the translation of viral mRNA in cells. 克里米亚刚果出血热病毒核衣壳蛋白与eIF4A相互作用，促进细胞内病毒mRNA的翻译。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-04 DOI: 10.1016/j.jbc.2025.110173

Saima Ali,Songyang Ren,Alexis Agsaoa,Sheema Mir,Mohammad A Mir

{"title":"The Nucleocapsid protein of Crimean Congo hemorrhagic fever virus interacts with eIF4A to promote the translation of viral mRNA in cells.","authors":"Saima Ali,Songyang Ren,Alexis Agsaoa,Sheema Mir,Mohammad A Mir","doi":"10.1016/j.jbc.2025.110173","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110173","url":null,"abstract":"Crimean-Congo hemorrhagic fever virus (CCHFV) is a tickborne nairovirus in the Bunyavirales order. Unlike many viral infections, CCHFV does not induce a host translation shutdown, posing the question of how its mRNAs are efficiently translated amidst competing host transcripts. Here, we show that the CCHFV nucleocapsid protein (N protein) enhances the translation of luciferase reporter mRNA with the help of the viral S-segment mRNA-derived 5' UTR. Chemical inhibition of eIF4E did not affect the N protein-mediated preferential translation of the reporter mRNA. However, translation shutdowns caused by either proteolytic cleavage of eIF4G or chemical inhibition of eIF4A abolished the N protein-mediated preferential translation of the reporter mRNA. These findings demonstrate that the CCHFV N protein requires both eIF4A and eIF4G to facilitate mRNA translation with the assistance of the viral mRNA 5' UTR. Randomization of the viral 5' UTR significantly reduced the translation efficiency of viral S-segment mRNA in cells. Our results demonstrate that wild type S-segment mRNA was heavily engaged with ribosomes, and N protein likely remained associated with the wild type 5' UTR, continuously facilitating ribosome loading, promoting polysome formation, and enhancing protein production. In contrast, most S-segment mRNA with a randomized 5' UTR was largely free from ribosome engagement, explaining the lower protein production from this transcript. Our results demonstrate that the N protein binds to eIF4A and likely reserves a population of eIF4A-eIF4G complexes that remain dedicated to selectively boost the translation of viral S-segment mRNA, thus avoiding competition from host cell transcripts for the same translation machinery.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"21 1","pages":"110173"},"PeriodicalIF":4.8,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915233","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}

引用次数: 0

SART1 uniquely localizes to spindle poles forming a SART1 cap and promotes spindle pole assembly. SART1独特地定位到主轴杆形成一个SART1帽和促进主轴杆组装。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-02 DOI: 10.1016/j.jbc.2025.108561

Hideki Yokoyama, Daniel Moreno-Andrés, Kaoru Takizawa, Zhenzhen Chu, Anja Scheufen, Tsumugi Funabashi, Jian Ma, Wolfram Antonin, Oliver J Gruss, Yoshikazu Haramoto

{"title":"SART1 uniquely localizes to spindle poles forming a SART1 cap and promotes spindle pole assembly.","authors":"Hideki Yokoyama, Daniel Moreno-Andrés, Kaoru Takizawa, Zhenzhen Chu, Anja Scheufen, Tsumugi Funabashi, Jian Ma, Wolfram Antonin, Oliver J Gruss, Yoshikazu Haramoto","doi":"10.1016/j.jbc.2025.108561","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.108561","url":null,"abstract":"The nuclear protein SART1 has been associated with pre-mRNA splicing, but SART1 RNAi knockdown results also in defects in mitotic progression, centrosome biogenesis, and chromosome cohesion. The mitotic roles of SART1 have not been characterized in detail, and it remains unclear whether SART1 functions in mitosis directly or indirectly via pre-mRNA splicing. Here, we identify SART1 as a direct, mitosis-specific microtubule-associated protein. SART1 downregulation in human cells leads to spindle assembly defects with reduced microtubule dynamics, end-on attachment defects, and checkpoint activation, while microtubule dynamics remain unaffected in interphase. SART1 uniquely localizes to the distal surface of mitotic centrosomes along the spindle axis, forming a previously not described structure we refer to as SART1 cap. Immunoprecipitation of SART1 consistently identifies centrosomal proteins as interaction partners. Immunostaining of these shows that SART1 downregulation does not affect centriole duplication and centrosome-accumulation of γ-tubulin but reduces the accumulation of selective pericentriolar material (PCM) proteins such as Ninein. Depletion of SART1 from frog egg extracts disrupts spindle pole assembly around sperm nuclei and DNA-coated beads. Spindles formed around DNA-coated beads do not contain centrosomes but still recruit PCM proteins for spindle pole assembly. We finally show that the N-terminus of SART1 is its microtubule-binding region and is essential for spindle assembly. Our data unravel a unique localization of SART1 and its novel function to recruit selective PCM proteins for spindle pole assembly in centrosomal and acentrosomal spindle assembly.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108561"},"PeriodicalIF":4.0,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144018050","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}

引用次数: 0

A 36-base hairpin within lncRNA DRAIC, which is modulated by alternative splicing, interacts with the IKKα coiled-coil domain and inhibits NF-κB and tumor cell phenotypes. lncRNA DRAIC中的一个36碱基发夹，通过选择性剪接调节，与IKKα线圈结构域相互作用，抑制NF-κB和肿瘤细胞表型。

IF 4 2区生物学

Journal of Biological Chemistry Pub Date : 2025-05-02 DOI: 10.1016/j.jbc.2025.110172

Xiaoxiao Hao, Yuechuan Chen, Divya Sahu, Róża K Przanowska, Mujawar Aaiyas, Chase A Weidmann, Isaac Nardi, Kevin M Weeks, Anindya Dutta

{"title":"A 36-base hairpin within lncRNA DRAIC, which is modulated by alternative splicing, interacts with the IKKα coiled-coil domain and inhibits NF-κB and tumor cell phenotypes.","authors":"Xiaoxiao Hao, Yuechuan Chen, Divya Sahu, Róża K Przanowska, Mujawar Aaiyas, Chase A Weidmann, Isaac Nardi, Kevin M Weeks, Anindya Dutta","doi":"10.1016/j.jbc.2025.110172","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.110172","url":null,"abstract":"A tumor-suppressive long noncoding RNA (lncRNA) DRAIC (down-regulated RNA in cancers) inhibits NF-κB activity and physically interacts with IKKα, a kinase component of the IKK complex, in several cancer types. Here we explore the precise molecular mechanism involved in this interaction and suppression. Using SHAPE-MaP, we identified a 36-nucleotide hairpin (A+B) within DRAIC that is necessary and sufficient for its anti-oncogenic function. RNA immunoprecipitation (RIP) and Electrophoretic mobility shift assays (EMSA) confirmed this hairpin physically interacts with the coiled coil domain of IKKα. A+B RNA has a high binding affinity (KD ∼1-7 nM) to the coiled-coil domain of IKKα. The binding of A+B disrupts the dimerization of NEMO and IKKα coiled-coil domains, a critical step for IKK action. Consistent with this, A+B inhibits the phosphorylation of the NF-κB inhibitor IκBα and suppresses NF-κB activity. Publicly available tumor RNAseq data revealed that alternative splicing modulates the presence of this critical hairpin: the inclusion of exon 4a (encoding one side of the A+B hairpin) in lung tumors correlates with reduced NF-κB activity. By demonstrating that the A+B hairpin is both necessary and sufficient to inhibit IKK and oncogenic phenotypes, this study underscores the centrality of IKKα interaction and NF-κB inhibition in DRAIC-mediated cancer suppression and indicates that the activity of this lncRNA is regulated by alternative splicing. This study also reveals the first example of a short RNA disrupting coiled-coil dimerization, offering a new approach to disrupt such dimerization in cancer biology.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"110172"},"PeriodicalIF":4.0,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036024","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}

引用次数: 0

Altering the ligand specificity of DectiSomes. 改变十体的配体特异性。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-04-30 DOI: 10.1016/j.jbc.2025.108566

Suresh Ambati,Xiaorong Lin,Zachary A Lewis,Richard B Meagher

{"title":"Altering the ligand specificity of DectiSomes.","authors":"Suresh Ambati,Xiaorong Lin,Zachary A Lewis,Richard B Meagher","doi":"10.1016/j.jbc.2025.108566","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.108566","url":null,"abstract":"DectiSomes are drug-loaded liposomes coated with pathogen receptors, such as the C-type lectins (CTL) Dectin-2 (D2) and Dectin-3 (D3, MCL). Floating on the surface of DectiSomes, the carbohydrate recognition domains (CRDs) of these CTLs form dimers that bind their cognate oligoglycan ligands. We have shown previously that amphotericin B (AmB)-loaded DectiSomes, D2-AmB-LLs and D3-AmB-LLs, are effective at binding and killing diverse pathogenic fungi. The best-known ligands of Dectin-2 and Dectin-3 in the Candida albicans cell wall and exopolysaccharide matrix include a wide variety of oligomannans. When D2-AmB-LLs or D3-AmB-LLs were labeled in their lumen with complementary green and red fluorescent proteins, Venus and mCherry, they bound the same overlapping regions of oligoglycans in C. albicans colonies. By contrast, when D2-AmB-LLs and D3-AmB-LLs were labeled on their membrane surfaces with complementary pairs of the small fluorophores FITC and Rhodamine B or with Venus and mCherry, they bound mostly non-overlapping sets of ligands. When the Dectin-2 and Dectin-3 proteins were labeled with the complementary pairs of FITC and Rhodamine, they also bound primarily distinct ligands. We proposed several models to explain these alterations in Dectin and DectiSome ligand specificity. These findings also raise important questions about the ligand binding properties of immuno-liposomes.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"34 1","pages":"108566"},"PeriodicalIF":4.8,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903097","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}

引用次数: 0

Live Cell Analysis of Mobility and Decay Kinetics of the Histone Variant H3.3. 组蛋白变异H3.3的活细胞迁移率和衰变动力学分析。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-04-30 DOI: 10.1016/j.jbc.2025.108557

Vishal Nehru,David Ball,Abhishek Mukherjee,Daisuke Kurotaki,Tatiana S Karpova,Keiko Ozato

{"title":"Live Cell Analysis of Mobility and Decay Kinetics of the Histone Variant H3.3.","authors":"Vishal Nehru,David Ball,Abhishek Mukherjee,Daisuke Kurotaki,Tatiana S Karpova,Keiko Ozato","doi":"10.1016/j.jbc.2025.108557","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.108557","url":null,"abstract":"Incorporation of the variant histone H3.3 into the genome occurs in conjunction with gene expression throughout the cell cycle. However, its precise regulatory mechanisms remain unclear. Traditional methods like Chromatin Immunoprecipitation provide static snapshots of H3.3 distribution that do not provide dynamic insights. To understand H3.3 behavior in live cells, we conducted fluorescence recovery after photobleaching (FRAP) to examine H3.3 mobility in mouse embryonic fibroblasts. The SNAP tag system enabled us to study the mobility of both preexisting and newly synthesized H3.3 pools. Our results showed that H3.3 is significantly more mobile than the core histone H3.1 during the 8-hour FRAP assay. Remarkably, H3.3 mobility was abolished under global transcription inhibition. Furthermore, the deletion of histone chaperone HIRA and NSD2 substantially reduced H3.3 mobility. We also investigated the turnover, or decay dynamics, of H3.3 using live-cell imaging over two days. Similar to its mobility, H3.3 decay was significantly delayed when transcription was inhibited and when HIRA and NSD2 were deleted. Our findings reveal that H3.3 dynamics and turnover are driven by ongoing transcription and depend on chaperone mediated H3.3 loading onto chromatin.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"137 1","pages":"108557"},"PeriodicalIF":4.8,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903100","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}

引用次数: 0

An uncharacterized gene from the Actinobacillus genus encodes a glucosyltransferase with successive transfer activity and unique substrate specificity. 放线菌属的一个未知基因编码葡萄糖基转移酶，具有连续转移活性和独特的底物特异性。

IF 4.8 2区生物学

Journal of Biological Chemistry Pub Date : 2025-04-30 DOI: 10.1016/j.jbc.2025.108567

Takahiro Yamasaki,Daisuke Kohda

{"title":"An uncharacterized gene from the Actinobacillus genus encodes a glucosyltransferase with successive transfer activity and unique substrate specificity.","authors":"Takahiro Yamasaki,Daisuke Kohda","doi":"10.1016/j.jbc.2025.108567","DOIUrl":"https://doi.org/10.1016/j.jbc.2025.108567","url":null,"abstract":"Elucidating the functions of glycosyltransferases is a necessary step toward understanding their biological roles and producing drug leads, cosmetics, and foods that utilize glycans as functional molecules. We found a previously uncharacterized protein classified as a glycosyltransferase encoded in the Actinobacillus minor NM305 genome and named the gene product AmGGT (Actinobacillus minor glucoside-glucosyltransferase). To clarify the biochemical properties of the AmGGT protein, we determined its substrate specificity and crystal structure. AmGGT exhibited processive glycosyltransferase activity when UDP-Glc was used as the donor substrate and, unexpectedly, showed different acceptor substrate specificity from that of the homologous Agt proteins of other Actinobacillus species. While the homologous proteins transfer glucose residues to the non-reducing end of oligosaccharide chains linked to peptides, AmGGT cannot use glycopeptides as acceptors and requires the non-reducing end of oligosaccharides. The crystal structure provided clues to identify a sequence motif consisting of two pairs of two amino acid residues that defines the acceptor specificity, oligosaccharide or glycopeptide. Based on this discovery, the acceptor substrate of AmGGT was changed from an oligosaccharide to a glycopeptide by transplanting the sequence motif from the homologous proteins. Furthermore, the AmGGT protein could utilize eukaryotic high-mannose type N-glycans as acceptors, as a model for branched oligosaccharides. The sequential glucosyltransfer activity and controllable substrate specificity of AmGGT will make it a useful tool in glycosyltransferase engineering to synthesize functional glycans and glycoconjugates.","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":"1135 1","pages":"108567"},"PeriodicalIF":4.8,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903110","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}

引用次数: 0