Pctaire1 interacts with p35 and is a novel substrate for Cdk5/p35

J Biol Chem. 2002 Aug 30;277(35):31988-93. doi: 10.1074/jbc.M201161200. Epub 2002 Jun 25.

Abstract

Cyclin-dependent kinase 5 (Cdk5) is a serine/threonine kinase that plays important roles during central nervous system development. Cdk5 kinase activity depends on its regulatory partners, p35 or p39, which are prominently expressed in the central nervous system. We have previously demonstrated the involvement of Cdk5 in the regulation of acetylcholine receptor expression at the neuromuscular junction, suggesting a novel functional role of Cdk5 at the synapse. Here we report the identification of Pctaire1, a member of the Cdk-related kinase family, as a p35-interacting protein in muscle. Binding of Pctaire1 to p35 can be demonstrated by in vitro binding assay and co-immunoprecipitation experiments. Pctaire1 is associated with p35 in cultured myotubes and skeletal muscle, and is concentrated at the neuromuscular junction. Furthermore, Pctaire1 can be phosphorylated by the Cdk5/p25 complex, and serine 95 is the major phosphorylation site. In brain and muscle of Cdk5 null mice, Pctaire1 activity is significantly reduced. Moreover, Pctaire1 activity is increased following preincubation with brain extracts and phosphorylation by the Cdk5/p25 complex. Taken together, our findings demonstrate that Pctaire1 interacts with p35, both in vitro and in vivo, and that phosphorylation of Pctaire1 by Cdk5 enhances its kinase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Brain / enzymology
  • COS Cells
  • Chlorocebus aethiops
  • Cyclin-Dependent Kinase 5
  • Cyclin-Dependent Kinases / metabolism*
  • Mice
  • Mice, Knockout
  • Muscle, Skeletal / enzymology
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Rats
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Substrate Specificity
  • Transfection

Substances

  • Nerve Tissue Proteins
  • Recombinant Fusion Proteins
  • Recombinant Proteins
  • neuronal Cdk5 activator (p25-p35)
  • Cyclin-Dependent Kinase 5
  • Protein-Serine-Threonine Kinases
  • Cdk5 protein, mouse
  • Cdk5 protein, rat
  • Cyclin-Dependent Kinases
  • PCTAIRE-1 protein kinase