The small GTP-binding protein Rho binds to and activates a 160 kDa Ser/Thr protein kinase homologous to myotonic dystrophy kinase

EMBO J. 1996 Apr 15;15(8):1885-93.

Abstract

The small GTP-binding protein Rho functions as a molecular switch in the formation of focal adhesions and stress fibers, cytokinesis and transcriptional activation. The biochemical mechanism underlying these actions remains unknown. Using a ligand overlay assay, we purified a 160 kDa platelet protein that bound specifically to GTP-bound Rho. This protein, p160, underwent autophosphorylation at its serine and threonine residues and showed the kinase activity to exogenous substrates. Both activities were enhanced by the addition of GTP-bound Rho. A cDNA encoding p160 coded for a 1354 amino acid protein. This protein has a Ser/Thr kinase domain in its N-terminus, followed by a coiled-coil structure approximately 600 amino acids long, and a cysteine-rich zinc finger-like motif and a pleckstrin homology region in the C-terminus. The N-terminus region including a kinase domain and a part of coiled-coil structure showed strong homology to myotonic dystrophy kinase over 500 residues. When co-expressed with RhoA in COS cells, p160 was co-precipitated with the expressed Rho and its kinase activity was activated, indicating that p160 can associate physically and functionally with Rho both in vitro and in vivo.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers / genetics
  • DNA, Complementary / genetics
  • Enzyme Activation
  • GTP-Binding Proteins / metabolism*
  • Humans
  • In Vitro Techniques
  • Molecular Sequence Data
  • Molecular Structure
  • Molecular Weight
  • Myotonic Dystrophy / enzymology*
  • Myotonin-Protein Kinase
  • Protein Binding
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Sequence Homology, Amino Acid
  • Transfection
  • rho GTP-Binding Proteins

Substances

  • DMPK protein, human
  • DNA Primers
  • DNA, Complementary
  • Myotonin-Protein Kinase
  • Protein-Serine-Threonine Kinases
  • GTP-Binding Proteins
  • rho GTP-Binding Proteins

Associated data

  • GENBANK/L08835
  • GENBANK/U43195
  • GENBANK/Z22521