Correct mitotic spindle size is required for accurate chromosome segregation during cell division. It is controlled by mechanical forces generated by molecular motors and non-motor proteins acting on spindle microtubules. However, how forces generated by individual proteins enable bipolar spindle organization is not well understood. Here, we develop tools to measure contributions of individual molecules to this force balance. We show that microtubule plus-end binding proteins act at microtubule tips synergistically with minus-end directed motors to produce a system that can generate both pushing and pulling forces. To generate pushing force, the system harnesses forces generated by the growing tips of microtubules providing unique contribution to the force balance distinct from all other motors that act in the mitotic spindle. Our results reveal that microtubules are essential force generators for establishing spindle size and pave the way for understanding how mechanical forces can be fine-tuned to control the fidelity of chromosome segregation.
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http://dx.doi.org/10.1038/s41467-024-54123-2 | DOI Listing |
Genes Chromosomes Cancer
January 2025
Department of Pathology, NYU Grossman School of Medicine, New York, New York, USA.
Gene fusions involving JAZF1 are a recurrent event in low grade endometrial stromal sarcoma, and have been more recently described in few instances of endometrial stromal sarcoma-like tumors in the genitourinary tract of men. In this article, we describe a previously unreported spindle cell sarcoma harboring an in-frame JAZF1::NUDT5 gene fusion, arising in the chest wall of a 51-year-old man. The tumor had unique morphologic features resembling both endometrial stromal sarcoma and endometrial stromal sarcoma-like tumors, consisting of a mixture of cytologically bland and pleomorphic spindle cells with brisk mitotic activity, within an alternating myxoid and fibrous stroma.
View Article and Find Full Text PDFJ Cell Biol
April 2025
Department of Genetics and Cell Biology, College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
TBC1D20 deficiency causes Warburg Micro Syndrome in humans, characterized by multiple eye abnormalities, severe intellectual disability, and abnormal sexual development, but the molecular mechanisms remain unknown. Here, we identify TBC1D20 as a novel Rab11 GTPase-activating protein that coordinates vesicle transport and actin remodeling to regulate ciliogenesis. Depletion of TBC1D20 promotes Rab11 vesicle accumulation and actin deconstruction around the centrosome, facilitating the initiation of ciliogenesis even in cycling cells.
View Article and Find Full Text PDFPrimary cilia play a pivotal role in cellular signaling and development and disruptions in ciliary form and/or function leads to human ciliopathies. Here, we examine the role of , a key component of the intraflagellar transport-A complex, in mouse forebrain development using a null allele. Our findings reveal significant microcephaly in homozygous mutants is caused by disrupted neural progenitor proliferation and differentiation.
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View Article and Find Full Text PDFBMC Cancer
January 2025
Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, MP, India.
Epstein-Barr virus (EBV), an oncogenic gamma-herpesvirus, belongs to group 1 carcinogen and is implicated in various cancers, including gastric cancer. Aurora Kinase A is a major mitotic protein kinase that regulates mitotic progression; overexpression and hyperactivation of AURKA commonly promote genomic instability in many tumours. However, the relationship of functional residues of AURKA and EBV in gastric cancer progression remains unknown.
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