Proteolysis of γ-tubulin small complex proteins is mediated by the ubiquitin-proteasome system

FEBS Letters

article

Can Yin¹  Edna S. W. Lui¹  Taolue Jiang¹  Robert Z. Qi¹ 

[1] Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology

关键词: cullin–RING ligase;    ubiquitination;    ubiquitin-proteasome system;    γ-tubulin;    γ-tubulin ring complex;    γ-tubulin small complex;   

DOI  :  10.1002/1873-3468.14146

来源: John Wiley & Sons Ltd.

【 摘 要 】

Microtubule nucleation is mainly mediated by the γ-tubulin ring complex (γTuRC), whose core components are γ-tubulin and γ-tubulin complex proteins GCP2–6. A substantial fraction of γ-tubulin also exists with GCP2 and GCP3 in a tetramer called the γ-tubulin small complex (γTuSC). To date, the mechanisms underlying the turnover of γ-tubulin and GCPs have remained unclear. Here, we show that γ-tubulin, GCP2, and GCP3 are proteolyzed by the ubiquitin-proteasome system, and we identify cullin 1, cullin 4A, and cullin 4B as the E3 ligases that mediate the ubiquitination and, consequently, the degradation of γ-tubulin. Notably, we found that γTuSC disassembly promotes the degradation of γ-tubulin, GCP2, and GCP3, which indicates a role for γTuSCs in the stabilization of its components.

【 授权许可】

Unknown