Interplay between components of a novel LIM kinase-slingshot phosphatase complex regulates cofilin

EMBO J. 2005 Feb 9;24(3):473-86. doi: 10.1038/sj.emboj.7600543. Epub 2005 Jan 20.

Abstract

Slingshot (SSH) phosphatases and LIM kinases (LIMK) regulate actin dynamics via a reversible phosphorylation (inactivation) of serine 3 in actin-depolymerizing factor (ADF) and cofilin. Here we demonstrate that a multi-protein complex consisting of SSH-1L, LIMK1, actin, and the scaffolding protein, 14-3-3zeta, is involved, along with the kinase, PAK4, in the regulation of ADF/cofilin activity. Endogenous LIMK1 and SSH-1L interact in vitro and co-localize in vivo, and this interaction results in dephosphorylation and downregulation of LIMK1 activity. We also show that the phosphatase activity of purified SSH-1L is F-actin dependent and is negatively regulated via phosphorylation by PAK4. 14-3-3zeta binds to phosphorylated slingshot, decreases the amount of slingshot that co-sediments with F-actin, but does not alter slingshot activity. Here we define a novel ADF/cofilin phosphoregulatory complex and suggest a new mechanism for the regulation of ADF/cofilin activity in mediating changes to the actin cytoskeleton.

Publication types

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

MeSH terms

  • 14-3-3 Proteins / chemistry
  • 14-3-3 Proteins / genetics
  • 14-3-3 Proteins / metabolism
  • Actin Depolymerizing Factors
  • Actins / metabolism
  • Animals
  • Binding Sites
  • Cell Line
  • Chickens
  • Destrin
  • Humans
  • In Vitro Techniques
  • Lim Kinases
  • Microfilament Proteins / chemistry*
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Models, Biological
  • Multiprotein Complexes
  • Neurons / metabolism
  • Phosphoprotein Phosphatases / chemistry*
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism*
  • Protein Kinases / chemistry*
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Serine-Threonine Kinases / chemistry
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Structure, Tertiary
  • Rats
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • p21-Activated Kinases

Substances

  • 14-3-3 Proteins
  • Actin Depolymerizing Factors
  • Actins
  • DSTN protein, human
  • Destrin
  • Microfilament Proteins
  • Multiprotein Complexes
  • Recombinant Fusion Proteins
  • Protein Kinases
  • PAK4 protein, human
  • LIMK1 protein, human
  • Lim Kinases
  • Limk1 protein, rat
  • Protein Serine-Threonine Kinases
  • p21-Activated Kinases
  • Phosphoprotein Phosphatases
  • SSH1 protein, human