Accession Number : ADA314743

Title :   Characterization of Ligand-Induced Endocytosis of EGF - Receptors.

Descriptive Note : Annual rept. 9 May 95-8 May 96,

Corporate Author : SCRIPPS RESEARCH INST LA JOLLA CA

Personal Author(s) : Schmid, Sandra L. ; LAmaze, Christophe

PDF Url : ADA314743

Report Date : JUN 1996

Pagination or Media Count : 24

Abstract : We have made progress this year in engineering and using a cell line that is conditionally defective in receptor-mediated endocytosis to directly assess the role of endocytosis in controlling cellular responses to activated EGF-R. We find, not surprisingly, that cells defective in endocytosis show a stronger proliferative response to FGF than wt cells. Surprisingly, we find that some EGF-R signaling pathways, specifically the MAP kinase activation and EGF-R phosphorylation itself are reduced in mutant cells relative to wt cells. Thus, endocytosis plays a role in specifying EGF-R signaling events, not just in attenuating them. Given the importance of endocytosis in EGF-R signaling our discovery, that Rho-family GTPases which are activated in response to growth factors are negative regulators of receptor-mediated endocytosis, may have important implications or control of receptor signalling. Finally we have begun to examine the role of epsl5, a tyrosine kinase substrate of the EGF-R which binds constitutively to the AP2 endocytic coat proteins, on endocytosis of EGF-R using our in vitro assay.

Descriptors :   *CELLS(BIOLOGY), *GROWTH(PHYSIOLOGY), *ONCOGENIC VIRUSES, *BREAST CANCER, CONTROL, PROTEINS, MUTATIONS, IN VITRO ANALYSIS, RESPONSE, SIGNALS, LIGANDS, ASSAYING, SENSE ORGANS, TYROSINE.

Subject Categories : Genetic Engineering and Molecular Biology
      Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE