APC(CDH1) Targets MgcRacGAP for Destruction in the Late M Phase

作者：Nishimura Koutarou; Oki Toshihiko; Kitaura Jiro; Kuninaka Shinji; Saya Hideyuki; Sakaue Sawano Asako; Miyawaki Atsushi; Kitamura Toshio^*

来源：PLos One, 2013, 8(5): e63001.

DOI：10.1371/journal.pone.0063001

Background: Male germ cell RacGTPase activating protein (MgcRacGAP) is an important regulator of the Rho family GTPases - RhoA, Rac1, and Cdc42 - and is indispensable in cytokinesis and cell cycle progression. Inactivation of RhoA by phosphorylated MgcRacGAP is an essential step in cytokinesis. MgcRacGAP is also involved in G1-S transition and nuclear transport of signal transducer and activator of transcription 3/5 (STAT3/5). Expression of MgcRacGAP is strictly controlled in a cell cycle-dependent manner. However, the underlying mechanisms have not been elucidated.
Methodology/Principal Findings: Using MgcRacGAP deletion mutants and the fusion proteins of full-length or partial fragments of MgcRacGAP to mVenus fluorescent protein, we demonstrated that MgcRacGAP is degraded by the ubiquitin-proteasome pathway in the late M to G1 phase via APC(CDH1). We also identified the critical region for destruction located in the C-terminus of MgcRacGAP, AA537-570, which is necessary and sufficient for CDH1-mediated MgcRacGAP destruction. In addition, we identified a PEST domain-like structure with charged residues in MgcRacGAP and implicate it in effective ubiquitination of MgcRacGAP.
Conclusions/Significance: Our findings not only reveal a novel mechanism for controlling the expression level of MgcRacGAP but also identify a new target of APC(CDH1). Moreover our results identify a C-terminal region AA537-570 of MgcRacGAP as its degron.

• 出版日期2013-5-16
• 单位河北医科大学