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Mitotic and meiotic cells contain a bipolar spindle apparatus of microtubules and associated proteins. To arrange microtubules into focused spindle poles, different mechanisms are used by various organisms. Principally, two major pathways have been characterized: nucleation and anchorage of microtubules at preexisting centers such as centrosomes or spindle pole bodies, or microtubule growth off the surface of chromosomes, followed by sorting and focusing into spindle poles. These two mechanisms can even be found in cells of the same organism: whereas most somatic animal cells utilize the centrosome as an organizing center for spindle microtubules, female meiotic cells build an acentriolar spindle apparatus. Most interestingly, the molecular components that drive acentriolar spindle pole formation are also present in cells containing centrosomes. They include microtubule-dependent motor proteins and a variety of structural proteins that regulate microtubule orientation, anchoring, and stability. The first of these spindle pole proteins, NuMA, had already been identified more than 20 years ago. In addition, several new proteins have been characterized more recently. This review discusses their role during spindle formation and their regulation in the cell cycle.
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http://dx.doi.org/10.1016/S0074-7696(04)38001-0 | DOI Listing |
Sci Rep
March 2025
Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA.
Centrosomes are critical organelles associated with the nucleus, consisting of a pair of centrioles surrounded by a cloud of pericentriolar material. They serve as key nucleation sites for microtubule arrays and are essential for positioning the nucleus prior to cell division, but mechanisms for ensuring proper centrosome positioning are not well understood. Previous research has identified asymmetries in microtubule arrays nucleated by centrosomes prior to cell division, including during the first cell cycle in Caenorhabditis elegans, as playing a critical role in centrosome positioning, however the origin of this asymmetry remains unclear.
View Article and Find Full Text PDFMol Genet Genomics
March 2025
State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine, Macau University of Science and Technology, Macau, China.
Clear cell renal cell carcinoma (ccRCC) is the urological malignancy with the highest incidence, centrosome amplification-associated genes (CARGs) have been suggested to be associated with carcinogenesis, but their roles in ccRCC are still incompletely understood. This study utilizes bioinformatics to explore the role of CARGs in the pathogenesis of ccRCC and to establish a prognostic model for ccRCC related to CARGs. Based on publicly available ccRCC datasets, 2312 differentially expressed genes (DEGs) were identified (control vs.
View Article and Find Full Text PDFThe γ-tubulin ring complex (γ-TuRC) acts as a structural template for microtubule formation at centrosomes, associating with two main compartments: the pericentriolar material and the centriole lumen. In the pericentriolar material, the γ-TuRC is involved in microtubule organization, while the function of the centriole lumenal pool remains unclear. The conformational landscape of the γ-TuRC, which is crucial for its activity, and its centrosomal anchoring mechanisms, which determine γ-TuRC activity and turnover, are not understood.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
March 2025
Biology Department, Mount Saint Vincent University, Halifax, Canada.
The organization of microtubules into a mitotic spindle is critical for animal cell proliferation and involves the cooperation of hundreds of proteins whose molecular roles and regulation are not fully understood. The protein product of the Drosophila gene abnormal spindle, Asp, is a microtubule-associated protein required for correct mitotic spindle formation. To better understand the contribution of Asp to microtubule organization during spindle formation, we reverse-engineered flies to express a version of Asp (Asp), predicted to have lost its ability to bind the phosphatase trimer PP2A-B56.
View Article and Find Full Text PDFElife
March 2025
Department of Biology, Washington University in St. Louis, St. Louis, United States.
Centrioles have a unique, conserved architecture formed by three linked, 'triplet', microtubules arranged in ninefold symmetry. The mechanisms by which these triplet microtubules are formed remain unclear but likely involve the noncanonical tubulins delta-tubulin and epsilon-tubulin. Previously, we found that human cells lacking delta-tubulin or epsilon-tubulin form abnormal centrioles, characterized by an absence of triplet microtubules, lack of central core protein POC5, and a futile cycle of centriole formation and disintegration (Wang et al.
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