2O8G: Rat Pp1c Gamma Complexed With Mouse Inhibitor-2

The functional specificity of type 1 protein phosphatases (PP1) depends on the associated regulatory/targeting and inhibitory subunits. To gain insights into the mechanism of PP1 regulation by inhibitor-2, an ancient and intrinsically disordered regulator, we solved the crystal structure of the complex to 2.5A resolution. Our studies show that, when complexed with PP1c, I-2 acquires three regions of order: site 1, residues 12-17, binds adjacent to a region recognized by many PP1 regulators; site 2, amino acids 44-56, interacts along the RVXF binding groove through an unsuspected sequence, KSQKW; and site 3, residues 130-169, forms alpha-helical regions that lie across the substrate-binding cleft. Specifically, residues 148-151 interact at the catalytic center, displacing essential metal ions, accounting for both rapid inhibition and slower inactivation of PP1c. Thus, our structure provides novel insights into the mechanism of PP1 inhibition and subsequent reactivation, has broad implications for the physiological regulation of PP1, and highlights common inhibitory interactions among phosphoprotein phosphatase family members.
PDB ID: 2O8GDownload
MMDB ID: 47448
PDB Deposition Date: 2006/12/12
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.5  Å
Source Organism:
Rattus norvegicus
Similar Structures:
Biological Unit for 2O8G: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 2O8G
Label Count Molecule
Proteins (2 molecules)
Serine/threonine-protein Phosphatase Pp1-gamma Catalytic Subunit(Gene symbol: Ppp1cc)
Molecule annotation
Protein Phosphatase Inhibitor 2(Gene symbol: Ppp1r2)
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB