Dual Ser and Thr phosphorylation of CPI-17, an inhibitor of myosin phosphatase, by MYPT-associated kinase

FEBS Lett. 2001 Mar 30;493(2-3):91-4. doi: 10.1016/s0014-5793(01)02277-3.

Abstract

Phosphorylation of CPI-17 and PHI-1 by the MYPT1-associated kinase (M110 kinase) was investigated. M110 kinase is a recently identified serine/threonine kinase with a catalytic domain that is homologous to that of ZIP kinase (ZIPK. GST-rN-ZIPK, a constitutively active GST fusion fragment, phosphorylates CPI-17 (but not PHI-1) to a stoichiometry of 1.7 mol/mol. Phosphoamino acid analysis revealed phosphorylation of both Ser and Thr residues. Phosphorylation sites in CPI-17 were identified as Thr 38 and Ser 12 using Edman sequencing with (32)P release and a point mutant of Thr 38.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins
  • Binding Sites
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Death-Associated Protein Kinases
  • In Vitro Techniques
  • Muscle Proteins / chemistry*
  • Muscle Proteins / genetics
  • Muscle Proteins / metabolism*
  • Myosin-Light-Chain Phosphatase
  • Phosphoprotein Phosphatases / antagonists & inhibitors*
  • Phosphoproteins / chemistry*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Point Mutation
  • Protein Serine-Threonine Kinases / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Serine / metabolism
  • Threonine / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Muscle Proteins
  • Phosphoproteins
  • Recombinant Fusion Proteins
  • Threonine
  • Serine
  • M110 kinase
  • Death-Associated Protein Kinases
  • Protein Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Phosphoprotein Phosphatases
  • Myosin-Light-Chain Phosphatase