Cdk5 Regulates Differentiation of Oligodendrocyte Precursor Cells Through the Direct Phosphorylation of Paxillin

J Cell Sci. 2007 Dec 15;120(Pt 24):4355-66. doi: 10.1242/jcs.018218. Epub 2007 Nov 27.

Abstract

Oligodendrocyte precursor cells (OPCs) differentiate into oligodendrocytes (OLs) in order to form myelin, which is required for the rapid propagation of action potentials in the vertebrate nervous system. In spite of the considerable clinical importance of myelination, little is known about the basic molecular mechanisms underlying OL differentiation and myelination. Here, we show that cyclin-dependent kinase (Cdk) 5 is activated following the induction of differentiation, and that the Cdk5 inhibitor roscovitine inhibits OL differentiation. The complexity of the OL processes is also diminished after knocking down endogenous Cdk5 using RNAi. We also show that the focal adhesion protein paxillin is directly phosphorylated at Ser244 by Cdk5. Transfection of a paxillin construct harboring a Ser244 to Ala mutation dramatically inhibits its morphological effects. Importantly, phosphorylation of paxillin at Ser244 reduces its interaction with focal adhesion kinase (FAK). Taken together, these results suggest that phosphorylation of paxillin by Cdk5 is a key mechanism in OL differentiation and may ultimately regulate myelination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation*
  • Cell Line
  • Cells, Cultured
  • Cyclin-Dependent Kinase 5 / antagonists & inhibitors
  • Cyclin-Dependent Kinase 5 / genetics
  • Cyclin-Dependent Kinase 5 / metabolism*
  • Focal Adhesion Kinase 1 / metabolism
  • Humans
  • Mice
  • Myelin Sheath / physiology*
  • Nerve Fibers, Myelinated / metabolism
  • Oligodendroglia / cytology*
  • Oligodendroglia / metabolism*
  • Paxillin / metabolism*
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Purines / pharmacology
  • RNA Interference
  • Rats
  • Rats, Sprague-Dawley
  • Roscovitine

Substances

  • Paxillin
  • Protein Kinase Inhibitors
  • Purines
  • Roscovitine
  • Focal Adhesion Kinase 1
  • Cyclin-Dependent Kinase 5