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PP1-mediated dephosphorylation of phosphoproteins at mitotic exit is controlled by inhibitor-1 and PP1 phosphorylation.
- Source :
- Nature Cell Biology; May2009, Vol. 11 Issue 5, p644-651, 8p, 10 Graphs
- Publication Year :
- 2009
-
Abstract
- Loss of cell division cycle 2 (Cdc2, also known as Cdk1) activity after cyclin B degradation is necessary, but not sufficient, for mitotic exit. Proteins phosphorylated by Cdc2 and downstream mitotic kinases must be dephosphorylated. We report here that protein phosphatase-1 (PP1) is the main catalyst of mitotic phosphoprotein dephosphorylation. Suppression of PP1 during early mitosis is maintained through dual inhibition by Cdc2 phosphorylation and the binding of inhibitor-1. Protein kinase A (PKA) phosphorylates inhibitor-1, mediating binding to PP1. As Cdc2 levels drop after cyclin B degradation, auto-dephosphorylation of PP1 at its Cdc2 phosphorylation site (Thr 320) allows partial PP1 activation. This promotes PP1-regulated dephosphorylation at the activating site of inhibitor-1 (Thr 35) followed by dissociation of the inhibitor-1–PP1 complex and then full PP1 activation to promote mitotic exit. Thus, Cdc2 both phosphorylates multiple mitotic substrates and inhibits their PP1-mediated dephosphorylation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14657392
- Volume :
- 11
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- Nature Cell Biology
- Publication Type :
- Academic Journal
- Accession number :
- 38593943
- Full Text :
- https://doi.org/10.1038/ncb1871