Protein kinase C controls microtubule-based traffic but not proteasomal degradation of c-Met

J Biol Chem. 2003 Aug 1;278(31):28921-9. doi: 10.1074/jbc.M302116200. Epub 2003 Apr 24.

Abstract

Upon hepatocyte growth factor stimulation, its receptor c-Met is rapidly internalized via clathrin-coated vesicles and traffics through an early endosomal compartment. We show here that c-Met accumulates progressively in perinuclear compartments, which in part include the Golgi. The c-Met content in the Golgi is principally the newly synthesized precursor form and, to a lesser extent, the internalized, recycling c-Met. By following the trafficking of c-Met inside the cell using a semi-automatic procedure and using inhibition or activation of protein kinase C (PKC) and microtubule depolymerizing agents, we show that PKC positively controls the trans-cytosolic movement of c-Met along microtubules. In parallel to its traffic, internalized c-Met is progressively degraded by a proteasome-sensitive mechanism; the lysosomal pathway does not play a substantial role. Inhibition or promotion of c-Met traffic to the perinuclear compartment does not alter the kinetics of proteasome-dependent c-Met degradation. Thus susceptibility to proteasomal degradation is not a consequence of post-endocytic traffic. The data define a PKC-controlled traffic pathway for c-Met that operates independently of its degradative pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Nucleus / metabolism
  • Cysteine Endopeptidases / metabolism*
  • Cytosol / metabolism
  • Endocytosis
  • Endosomes / metabolism
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Fluorescent Antibody Technique
  • Golgi Apparatus / metabolism
  • HeLa Cells
  • Hepatocyte Growth Factor / pharmacology
  • Humans
  • Indoles / pharmacology
  • Kinetics
  • Lysosomes / metabolism
  • Maleimides / pharmacology
  • Microscopy, Confocal
  • Microtubules / metabolism*
  • Multienzyme Complexes / metabolism*
  • Proteasome Endopeptidase Complex
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Proto-Oncogene Proteins c-met / metabolism*
  • Recombinant Proteins / pharmacology

Substances

  • Enzyme Inhibitors
  • Indoles
  • Maleimides
  • Multienzyme Complexes
  • Recombinant Proteins
  • Hepatocyte Growth Factor
  • Proto-Oncogene Proteins c-met
  • Protein Kinase C
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex
  • bisindolylmaleimide I