APC(CDH1) targets MgcRacGAP for destruction in the late M phase

PLoS One. 2013 May 16;8(5):e63001. doi: 10.1371/journal.pone.0063001. Print 2013.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD
  • Blotting, Western
  • Cadherins / genetics
  • Cadherins / metabolism*
  • Cdh1 Proteins / genetics
  • Cdh1 Proteins / metabolism*
  • Cell Cycle
  • Cell Line
  • Flow Cytometry
  • G1 Phase / genetics
  • G1 Phase / physiology
  • GTPase-Activating Proteins / genetics
  • GTPase-Activating Proteins / metabolism*
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Mice
  • NIH 3T3 Cells
  • Protein Binding
  • Resting Phase, Cell Cycle / genetics
  • Resting Phase, Cell Cycle / physiology

Substances

  • Antigens, CD
  • CDH1 protein, human
  • Cadherins
  • Cdh1 Proteins
  • Fzr1 protein, mouse
  • GTPase-Activating Proteins
  • mgcRacGAP

Grant support

This work was supported by Grant-in-Aid for Scientific Research on Innovative Areas (Grant number 22118002) and Grant-in-Aid Scientific Research (C) (Grant number 23591370), MEXT, Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.