Aberrant centrosome organisation with ensuing alterations of microtubule nucleation capacity enables tumour cells to proliferate and invade despite increased genomic instability. CEP192 is a key factor in the initiation process of centrosome duplication and in the control of centrosome microtubule nucleation. However, regulatory means of CEP192 have remained unknown. Here, we report that FBXL13, a binding determinant of SCF (SKP1-CUL1-F-box)-family E3 ubiquitin ligases, is enriched at centrosomes and interacts with the centrosomal proteins Centrin-2, Centrin-3, CEP152 and CEP192. Among these, CEP192 is specifically targeted for proteasomal degradation by FBXL13. Accordingly, induced FBXL13 expression downregulates centrosomal γ-tubulin and disrupts centrosomal microtubule arrays. In addition, depletion of FBXL13 induces high levels of CEP192 and γ-tubulin at the centrosomes with the consequence of defects in cell motility. Together, we characterise FBXL13 as a novel regulator of microtubule nucleation activity and highlight a role in promoting cell motility with potential tumour-promoting implications.
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http://dx.doi.org/10.15252/embr.201744799 | DOI Listing |
Int J Mol Sci
December 2024
Department of Biochemistry and Molecular Biology, Frederick P. Whiddon College of Medicine, Mobile, AL 36688, USA.
An intracellular protozoan, the Apicomplexan parasite () infects nucleated cells, in which it triggers the formation of a specialized membrane-confined cytoplasmic vacuole, named the parasitophorous vacuole (PV). One of the most prominent events in the parasite's intracellular life is the congregation of the host cell mitochondria around the PV. However, the significance of this event has remained largely unsolved since the parasite itself possesses a functional mitochondrion, which is essential for its replication.
View Article and Find Full Text PDFBiomedicines
December 2024
A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia.
The changes in the level of small GTPase ARL4C are associated with the initiation and progression of many different cancers. The content of ARL4C varies greatly between different tissues, and the induction of ARL4C expression leads to changes in cell morphology and proliferation. Although ARL4C can bind alpha-tubulin and affect intracellular transport, the role of ARL4C in the functioning of the tubulin cytoskeleton remained unclear.
View Article and Find Full Text PDFAnal Chem
January 2025
Institut de Recherche en Santé, Environnement et Travail (Irset)─Inserm─EHESP, UMR_S 1085, Université de Rennes, 9 av. du Professeur Léon Bernard, F-35042 Rennes, France.
Amyloidosis is a group of proteinopathies characterized by the systemic or organ-specific deposition of proteins in the form of amyloid fibers. Nearly 40 proteins play a role in these pathologies, and the structures of the associated fibers are beginning to be determined by Cryo-EM. However, the molecular events underlying the process, such as fiber nucleation and elongation, are poorly understood, which impairs developing efficient therapies.
View Article and Find Full Text PDFPLoS Biol
January 2025
Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America.
Microtubule nucleation is important for microtubule organization in dendrites and for neuronal injury responses. The core nucleation protein, γTubulin (γTub), is localized to dendrite branch points in Drosophila sensory neurons by Wnt receptors and scaffolding proteins on endosomes. However, whether Wnt ligands are important is unknown.
View Article and Find Full Text PDFNat Commun
January 2025
Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany.
The γ-tubulin ring complex (γ-TuRC) is a structural template for controlled nucleation of microtubules from α/β-tubulin heterodimers. At the cytoplasmic side of the yeast spindle pole body, the CM1-containing receptor protein Spc72 promotes γ-TuRC assembly from seven γ-tubulin small complexes (γ-TuSCs) and recruits the microtubule polymerase Stu2, yet their molecular interplay remains unclear. Here, we determine the cryo-EM structure of the Candida albicans cytoplasmic nucleation unit at 3.
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