Touré Aminata, Mzali Rym, Liot Caroline, Seguin Laetitia, Morin Laurence, Crouin Catherine, Chen-Yang Ilin, Tsay Yeou-Guang, Dorseuil Olivier, Gacon Gérard, Bertoglio Jacques
Institut Cochin, Département de Génétique et Développement, INSERM U567/CNRS UMR8104/Université Paris Descartes, 24 rue du Faubourg Saint Jacques, 75014 Paris, France.
FEBS Lett. 2008 Apr 9;582(8):1182-8. doi: 10.1016/j.febslet.2007.12.036. Epub 2008 Jan 15.
MgcRacGAP, a Rho GAP essential to cytokinesis, works both as a Rho GTPase regulator and as a scaffolding protein. MgcRacGAP interacts with MKLP1 to form the centralspindlin complex and associates with the RhoGEF Ect2. The GAP activity of MgcRacGAP is regulated by Aurora B phosphorylation. We have isolated B56epsilon, a PP2A regulatory subunit, as a new MgcRacGAP partner. We report here that (i) MgcRacGAP is phosphorylated by Aurora B and Cdk1, (ii) PP2A dephosphorylates Aurora B and Cdk1 phosphorylated sites and (iii) inhibition of PP2A abrogates MgcRacGAP/Ect2 interaction. Therefore, PP2A may regulate cytokinesis by dephosphorylating MgcRacGAP and its interacting partners.
MgcRacGAP是一种胞质分裂所必需的Rho GAP，它既作为Rho GTPase调节剂起作用，又作为支架蛋白起作用。MgcRacGAP与MKLP1相互作用形成中央纺锤体复合物，并与RhoGEF Ect2相关联。MgcRacGAP的GAP活性受Aurora B磷酸化调节。我们已分离出一种PP2A调节亚基B56epsilon作为新的MgcRacGAP伴侣。我们在此报告：（i）MgcRacGAP被Aurora B和Cdk1磷酸化；（ii）PP2A使Aurora B和Cdk1磷酸化位点去磷酸化；（iii）抑制PP2A可消除MgcRacGAP/Ect2相互作用。因此，PP2A可能通过使MgcRacGAP及其相互作用伴侣去磷酸化来调节胞质分裂。
