Molecular Biology of the Cell最新文献

{"title":"Knock-in reconstitution studies reveal an unexpected role of Cys-65 in regulating APE1/Ref-1 subcellular trafficking and function.","authors":"","doi":"10.1091/mbc.E11-05-0391-corr","DOIUrl":"10.1091/mbc.E11-05-0391-corr","url":null,"abstract":"","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":"36 10","pages":"cor2"},"PeriodicalIF":2.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12509286/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145200422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonmuscle myosin IIA (NMIIA) regulates anisotropic cell tension to maintain the hexagonal packing of mouse lens meridional row cells.","authors":"Sadia T Islam, Yiwen Tang, Heather Boliver, Dapeng Bi, Velia M Fowler","doi":"10.1091/mbc.E25-04-0154","DOIUrl":"10.1091/mbc.E25-04-0154","url":null,"abstract":"<p><p>The mouse ocular lens is an excellent vertebrate model for epithelial cell hexagonal packing during tissue morphogenesis. As lens epithelial cells differentiate into fiber cells, the epithelial cells rearrange into hexagonally packed meridional row (MR) cells that further differentiate to form fiber cells. We previously reported that the nonmuscle myosin IIA (NMIIA)-E1841K mutation, which alters NMIIA bipolar filament assembly, significantly disrupts MR cell hexagonal packing. Immunofluorescence microscopy of MR cells demonstrates increased enrichment of NMIIA, N-cadherin, and vinculin at anterior-posterior (AP)-oriented sides of control MR cells, but equal distributions on all sides of mutant MR cells. Furthermore, F-actin is uniformly distributed around all edges of control MR cells but reduced at the AP-oriented edges of mutant MR cells. Using Bayesian Mechanical Inference, we discovered that MR cells in control lenses exhibit anisotropic junctional tension, in which relative tension is more concentrated at the AP-oriented edges. In contrast, MR cells in mutant lenses show isotropic junctional tension on all sides. We conclude that the NMIIA-E1841K mutation results in altered F-actin, NMIIA, N-cadherin, and vinculin distributions, disrupting the anisotropic orientational pattern of mechanical forces within the tissue, leading to disordered cell packing during mouse lens epithelial cell differentiation.</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"ar124"},"PeriodicalIF":2.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12483326/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144961638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cell-APP: A generalizable method for cell annotation and cell-segmentation model training.","authors":"Anish J Virdi, Ajit P Joglekar","doi":"10.1091/mbc.E25-02-0076","DOIUrl":"10.1091/mbc.E25-02-0076","url":null,"abstract":"<p><p>Deep learning-based segmentation models can accelerate the analysis of high-throughput microscopy data by automatically identifying and classifying cells in images. However, the datasets needed to train these models are typically assembled via laborious hand-annotation. This limits their scale and diversity, which in turn limits model performance. We present Cell-APP (Cellular Annotation and Perception Pipeline), a tool that automates the annotation of high-quality training data for transmitted-light (TL) cell segmentation. Cell-APP uses two inputs-paired TL and nuclear fluorescence images-and operates in two main steps. First, it extracts each cell's location from the nuclear fluorescence channel and provides these locations to promptable deep learning models to generate cell masks. Then, it classifies each cell as mitotic or non-mitotic based on nuclear features. Together, these masks and classifications form the basis for cell segmentation training data. By training vision-transformer-based models on Cell-APP-generated datasets, we demonstrate how Cell-APP enables the creation of both cell line-specific and multi-cell line segmentation models. Cell-APP thus empowers laboratories to tailor cell segmentation models to their needs and outlines a scalable path to creating general models for the research community.</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE25020076"},"PeriodicalIF":2.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145138004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harnessing fusion of genome-edited human stem cells to rapidly screen for novel protein functions <i>in vivo</i>.","authors":"Samantha L Smith, Yuichiro Iwamoto, Aadhithya Manimaran, David G Drubin","doi":"10.1091/mbc.E25-06-0301","DOIUrl":"10.1091/mbc.E25-06-0301","url":null,"abstract":"<p><p>Genome editing has enabled the integration of fluorescent protein coding sequences into genomes, resulting in expression of in-frame fusion proteins under the control of their natural gene regulatory sequences. While this technique overcomes the well-documented artifacts associated with gene overexpression for biological processes sensitive to altered protein stoichiometry, such as clathrin-mediated endocytosis (CME), editing genomes of metazoan cells incurs a significant time cost compared to simpler organisms, such as yeast. Editing two or more genes to express multiple fluorescent fusion proteins in a single cell line has proven to be a powerful strategy for uncovering spatio-dynamic, and therefore functional, relationships among different proteins, but it can take many months to edit each gene within the same cell line. Here, by utilizing cell fusions, we quickly generated cells expressing pairwise permutations of fluorescent fusion proteins in genome-edited human cells to reveal previously undetected protein-organelle interactions. We fused human induced pluripotent stem cells (hiPSCs) that express in-frame fusions of CME and actin cytoskeleton proteins with hiPSCs that express fluorescently tagged organelle markers, uncovering novel interactions between CME proteins, branched actin filament networks, and lysosomes. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE25060301"},"PeriodicalIF":2.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145138091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Loss of CHMP2A implicates an ordered assembly of ESCRT-III proteins during cytokinetic abscission.","authors":"Nikita Kamenetsky, Dikla Nachmias, Suman Khan, Ori Avinoam, Itay Hazan, Alexander Upcher, Natalie Elia","doi":"10.1091/mbc.E25-06-0279","DOIUrl":"https://doi.org/10.1091/mbc.E25-06-0279","url":null,"abstract":"<p><p>The ESCRT machinery mediates membrane remodeling in fundamental cellular processes including cytokinesis, endosomal sorting, nuclear envelope reformation, and membrane repair. Membrane constriction and scission is driven by the filament-forming ESCRT-III complex and the AAA-ATPase VPS4. While ESCRT-III-driven membrane scission is generally established, the mechanisms governing the assembly and coordination of its twelve mammalian isoforms in cells remain poorly understood. Here, we examined the spatial organization and interdependence of ESCRT-III subunits during mammalian cytokinetic abscission by depleting CHMP2A, a core ESCRT-III component. Using live cell imaging, structured illumination microscopy (SIM) and correlative light-electron microscopy (CLEM), we show that CHMP2A knockout cells display a significant delay-but not failure-in abscission, accompanied by distinct mislocalization phenotypes across ESCRT-III subunits. While IST1 and CHMP2B were minimally disrupted, CHMP4B, CHMP3, and CHMP1B display progressively severe organization defects at the abscission site. Dual-protein imaging reveals disrupted coordination between ESCRT-III subunits in individual CHMP2A-deficient cells, supporting an ordered assembly of ESCRT-III subunits in cytokinetic abscission. Together, our findings provide the first in vivo evidence for hierarchical assembly of ESCRT-III subunits during ESCRT-mediated membrane remodeling and identify CHMP2A as a key organizer of ESCRT-III architecture essential for timely membrane abscission. [Media: see text] [Media: see text].</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE25060279"},"PeriodicalIF":2.7,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145033789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defining the Role of Integrins in Melanoblast Migration <i>In Vivo</i>.","authors":"Wenjun Deng, Guy Tanentzapf","doi":"10.1091/mbc.E25-02-0066","DOIUrl":"https://doi.org/10.1091/mbc.E25-02-0066","url":null,"abstract":"<p><p>During embryonic development, neural crest-derived melanoblasts, which are precursors of pigment-producing melanocytes, disperse throughout the skin by long-range cell migration that requires adhesion to the ECM. Members of the integrin family of cell-ECM adhesion receptors are thought to contribute to melanocyte migration <i>in vitro</i>. However, due to the functional redundancy between different integrin heterodimers, the precise role of integrins in melanoblast migration, as well as the mechanisms that regulate them in this process, especially in <i>in vivo</i> contexts, remain poorly understood. To address this, we utilize the existing transcriptomic databases to identify different integrin subunits that are specifically expressed in melanoblasts, melanocytes and melanoma cancer cell lines. We then use mouse embryonic skin explants combined with drug and small molecule-based perturbations to target different integrins as well as specific mechanisms that modulate integrin activity. Individual melanoblasts from live imaging movies are tracked using high-resolution, quantitative, automated analysis, and cell morphology, cell migration and actin-based protrusions are analyzed. Overall, we uncover the non-redundant roles of different integrin heterodimers and elucidate the function of outside-in integrin activation in melanoblasts. Finally, we describe the function played, <i>in vivo,</i> by integrin-mediated adhesion to specific ECM ligands during melanoblast migration. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE25020066"},"PeriodicalIF":2.7,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145033819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Hox Gene, <i>abdominal-A</i>, controls the size and timely mitotic entry of neural stem cells during CNS patterning in <i>Drosophila</i>.","authors":"Papri Das, Smrithi Murthy, Eshan Abbas, Kristin White, Richa Arya","doi":"10.1091/mbc.E24-08-0347","DOIUrl":"10.1091/mbc.E24-08-0347","url":null,"abstract":"<p><p>Cell size is strongly correlated with several biological processes, including the cell cycle and growth. Here, we investigated the regulation of stem cell size during <i>Drosophila</i> central nervous system (CNS) development and its association with cell fate. We note that neural stem cells (NSCs) in different regions of the ventral nerve cord increase their size at different rates. Thoracic NSCs grow at a faster rate compared to those in the abdominal region during larval development. We show that in addition to the known role in apoptosis and nervous system remodeling, larval expression of <i>abdA</i> is crucial in regulating the rate of postembryonic NSCs size increase, their timely exit from G2 phase and mitotic rate.  We demonstrate that when <i>abdA</i> expression is lost in abdominal NSCs, their size increases, they exhibit a shorter G2 phase, enter mitosis earlier, and divide more rapidly. Conversely, the introduction of <i>abdA</i> in thoracic NSCs slows their growth and delays their entry into mitosis. We demonstrate that <i>abdA</i>-mediated NSC size regulation acts downstream of their nutrition-induced activation, thereby fine-tuning the stem cell potential spatiotemporally. This study highlights the instructive role of <i>abdA</i> in regulating various fates of larval NSCs during CNS patterning.</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE24080347"},"PeriodicalIF":2.7,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144992899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acyl-coA binding protein AcbdA is required for peroxisome hitchhiking on early endosomes in <i>Aspergillus nidulans</i>.","authors":"Bellana Driscoll, Madison B Fountain, Isabella N Gates, Reihane Abdollahi, Allison M Langley, Matthew B Owens, Jenna R Christensen, John Salogiannis","doi":"10.1091/mbc.E25-04-0186","DOIUrl":"10.1091/mbc.E25-04-0186","url":null,"abstract":"<p><p>Motor-driven transport on microtubules is critical for distributing organelles throughout the cell. Most commonly, organelle movement is mediated by cargo adaptors, proteins on the surface of an organelle that directly recruit microtubule-based motors. An alternative mechanism called hitchhiking was recently discovered: some organelles move, not by recruiting the motors directly, but instead by using membrane contact sites to attach to motor-driven vesicles and hitchhike along microtubules. Organelle hitchhiking is observed across fungi and animals. In filamentous fungi, nearly all peroxisomes move by hitchhiking on early endosomes (EEs). In the fungus <i>Aspergillus nidulans</i>, EE-associated linker proteins PxdA and DipA are critical for establishing EE-peroxisome membrane contact sites required for peroxisome movement. Whether peroxisome-membrane proteins exist that regulate peroxisome hitchhiking on EEs is not known. Through a forward mutagenesis screen, we discovered an acyl-coA binding (ACB) domain-containing protein AcbdA/AN1062 that localizes to peroxisomes via its tail-anchored transmembrane domain (TMD). Deleting the AcbdA gene or only its N-terminal ACB domain perturbs the movement and distribution of peroxisomes. Importantly, AcbdA is not required for the movement of EEs or for the recruitment of PxdA and DipA on EEs. Fatty acid (FA)-induced increases in peroxisome movement require AcbdA, suggesting that peroxisome hitchhiking on EEs is coupled to FA metabolism. Mutating a conserved FFAT motif, predicted to interact with the endoplasmic reticulum (ER), has no effect on peroxisome movement. Taken together, our data indicate that AcbdA is a peroxisome-membrane protein required for peroxisome hitchhiking on EEs. AcbdA's involvement in peroxisome hitchhiking represents a divergence from known functions of Acbd4/5 proteins and adds layers to our understanding of the functionality of the Acbd4/5 family of proteins. [Media: see text] [Media: see text] [Media: see text].</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"mbcE25040186"},"PeriodicalIF":2.7,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144992962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microglia express Tie2 in a longitudinal imaging study of acute neural injury in mice.","authors":"Jennifer Brodsky, Zeinab Tashi, Sharon K Christopher, Rory Kruitoff, Mohammad Abbasi, Gabriella Cerna, Simone B Gohsman, Miyeko D Mana, Benjamin B Bartelle","doi":"10.1091/mbc.E25-05-0257","DOIUrl":"10.1091/mbc.E25-05-0257","url":null,"abstract":"<p><p>The Tie2 receptor tyrosine kinase is expressed both in stroke recovery and cancer progression by vascular endothelial and myeloid lineage cells. Tie2 mechanisms have been described in vascular maturation, but the receptor's immune role remains poorly understood. Here, we describe the expression of Tie2 in microglia in response to an acute neural injury, uncovering a potential new role for these cells. Using magnetic resonance imaging (MRI) and the Ts-Biotag multimodal reporter mouse, we noninvasively imaged Tie2 expression dynamics in a longitudinal study of neural injury to identify key timepoints in wound signaling and healing. Using labeled bone marrow chimeras, we further determined that Tie2 is expressed in brain-resident microglia but not invading macrophages. Our results establish the utility of noninvasive molecular imaging for longitudinal studies of neuroimmune function and present a new role for Tie2 as a uniquely expressed marker of microglial function during wound healing.</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"ar112"},"PeriodicalIF":2.7,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12415610/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144642945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Did axons evolve by activating cytokinesis during interphase? A hypothesis on the origin of neurons.","authors":"Kyle E Miller, Francesca Oprea, Sajid Alam, Ania Grodsky, Erin M Craig","doi":"10.1091/mbc.E24-12-0585","DOIUrl":"10.1091/mbc.E24-12-0585","url":null,"abstract":"<p><p>Although synaptic evolution has been extensively studied, how axons first arose remains unexplored. Because evolution often occurs by coopting existing features, we review the evolutionary histories, biophysics, and cell biology of cytokinesis, cell crawling, and ciliogenesis to explore the origin of axons. Although we found that cilia and axons are outwardly similar, and growth cones strongly resemble the leading edge of crawling cells, the biophysical processes and the critical proteins that drive each seem weakly linked to axons as a structure. In contrast, the traction force machinery that pulls daughter cells apart during cytokinesis and the cytoskeletal organization of cytokinetic bridges appear to have a one-to-one correspondence to neuronal growth cones and axons. Based on these observations, we propose the hypothesis that axons evolved due to mutations that partially activated cytokinesis in an interphase cell. To rigorously test this hypothesis, we suggest conducting systematic phylogenetic analysis of the genes essential for each process, paired with molecular genetic studies in which critical genes are systematically disrupted. Doing so will provide a framework for understanding the relationship between diverse cellular processes, the early evolution of neurons, and insights that could potentially assist in treating cancer and promoting neuronal regeneration.</p>","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":" ","pages":"ar110"},"PeriodicalIF":2.7,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12415613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}