title: Protein kinase C controls microtubule-based traffic but not proteasomal degradation of c-Met.
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.
authors.affiliation: Protein Phosphorylation Laboratory and Light Microscopy Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom. s.kermorgant@cancer.org.uk
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kermorgant
authors.forename: Daniel
authors.initials: D
authors.lastname: Zicha
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Parker
mesh_terms: D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism; D006367:HeLa Cells; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D008247:Lysosomes / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met; D011493:Protein Kinase C; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C070515:bisindolylmaleimide I