Title

Specific Grb2-mediated interactions regulate clathrin-dependent endocytosis of the cMet-tyrosine kinase

Authors

Authors

N. Li; M. Lorinczi; K. Ireton;L. A. Elferink

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

J. Biol. Chem.

Keywords

GROWTH-FACTOR RECEPTOR; GRB2 BINDING-SITE; PLECKSTRIN HOMOLOGY DOMAIN; MET RECEPTOR; C-CBL; EGF RECEPTOR; COATED PITS; LISTERIA-MONOCYTOGENES; SOMATIC MUTATIONS; ADAPTER PROTEIN; Biochemistry & Molecular Biology

Abstract

Lysosomal degradation of the receptor-tyrosine kinase cMet requires receptor ubiquitination by the E3 ubiquitin ligase Cbl followed by clathrin-dependent internalization. A role for Cbl as an adaptor for cMet internalization has been previously reported. However, the requirement for Cbl ubiquitin ligase activity in this process and its mode of recruitment to cMet has yet to be determined. Cbl can directly bind cMet at phosphotyrosine 1003 or indirectly via Grb2 to phosphotyrosine 1356 in the multisubstrate binding domain of cMet. The direct binding of Cbl with cMet is critical for receptor degradation and not receptor internalization. Here we show a strict requirement for Grb2 and the ubiquitin ligase activity of Cbl for cMet endocytosis. Receptor internalization was impaired by small interfering RNA depletion of Grb2, overexpression of dominant negative Grb2 mutants, and point mutations in the cMet multisubstrate docking site that inhibits the direct association of Grb2 with cMet. The requirement for Grb2 was specific and did not involve the multiadaptor Gab1. cMet internalization was impaired in cells expressing an ubiquitin ligase-deficient Cbl mutant or conjugation-deficient ubiquitin but was unaffected in cells expressing a Cbl mutant that is unable to bind cMet directly. Expression of a Cbl-Grb2 chimera rescued impaired cMet endocytosis in cells depleted of endogenous Grb2. These results indicate that the ubiquitin ligase activity of Cbl is critical for clathrin-dependent cMet internalization and suggest a role for Grb2 as an intermediary linking Cbl ubiquitin ligase activity to this process.

Journal Title

Journal of Biological Chemistry

Volume

282

Issue/Number

23

Publication Date

1-1-2007

Document Type

Article

Language

English

First Page

16764

Last Page

16775

WOS Identifier

WOS:000246946500008

ISSN

0021-9258

Share

COinS