1S70: Complex Between Protein Ser/thr Phosphatase-1 (delta) And The Myosin Phosphatase Targeting Subunit 1 (mypt1)

The coordinated and reciprocal action of serine/threonine (Ser/Thr) protein kinases and phosphatases produces transient phosphorylation, a fundamental regulatory mechanism for many biological processes. The human genome encodes a far greater number of Ser/Thr protein kinases than of phosphatases. Protein phosphatase 1 (PP1), in particular, is ubiquitously distributed and regulates a broad range of cellular functions, including glycogen metabolism, cell-cycle progression and muscle relaxation. PP1 has evolved effective catalytic machinery but lacks substrate specificity. Substrate specificity is conferred upon PP1 through interactions with a large number of regulatory subunits. The regulatory subunits are generally unrelated, but most possess the RVxF motif, a canonical PP1-binding sequence. Here we reveal the crystal structure at 2.7 A resolution of the complex between PP1 and a 34-kDa N-terminal domain of the myosin phosphatase targeting subunit MYPT1. MYPT1 is the protein that regulates PP1 function in smooth muscle relaxation. Structural elements amino- and carboxy-terminal to the RVxF motif of MYPT1 are positioned in a way that leads to a pronounced reshaping of the catalytic cleft of PP1, contributing to the increased myosin specificity of this complex. The structure has general implications for the control of PP1 activity by other regulatory subunits.
PDB ID: 1S70Download
MMDB ID: 28228
PDB Deposition Date: 2004/1/28
Updated in MMDB: 2006/12
Experimental Method:
x-ray diffraction
Resolution: 2.7  Å
Source Organism:
Homo sapiens
Similar Structures:
Biological Unit for 1S70: dimeric; determined by author and by software (PISA)
Molecular Components in 1S70
Label Count Molecule
Proteins (2 molecules)
Serine/threonine Protein Phosphatase Pp1-beta (OR Delta) Catalytic Subunit(Gene symbol: PPP1CB)
Molecule annotation
130 KDA Myosin-binding Subunit of Smooth Muscle Myosin Phophatase (M130)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB