Department of Oncology, Cancer Research UK and Medical Research Council Institute for Radiation Oncology, University of Oxford, Oxford, UK.
Department of Medicine III, Klinikum Rechts der Isar, Technische Universität München, München, Germany.
EMBO Rep. 2018 Mar;19(3). doi: 10.15252/embr.201744799. Epub 2018 Jan 18.
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.
异常的中心体组织,随之而来的微管成核能力的改变,使肿瘤细胞能够在基因组不稳定性增加的情况下增殖和侵袭。CEP192 是中心体复制起始过程和控制中心体微管成核的关键因素。然而,CEP192 的调节方式仍然未知。在这里,我们报告 FBXL13,一种 SCF(SKP1-CUL1-F-box)家族 E3 泛素连接酶的结合决定因素,在中心体上富集,并与中心体蛋白 Centrin-2、Centrin-3、CEP152 和 CEP192 相互作用。在这些蛋白中,CEP192 被 FBXL13 特异性靶向蛋白酶体降解。因此,诱导 FBXL13 表达会下调中心体 γ-微管蛋白并破坏中心体微管阵列。此外,FBXL13 的耗竭会导致中心体中 CEP192 和 γ-微管蛋白水平升高,从而导致细胞运动缺陷。总之,我们将 FBXL13 表征为微管成核活性的新型调节剂,并强调其在促进细胞运动中的作用,这可能具有肿瘤促进作用。