The c-Cbl/CD2AP complex regulates VEGF-induced endocytosis and degradation of Flt-1 (VEGFR-1).
Vascular endothelial growth factor (VEGF) and its receptors are key regulators of angiogenesis and are potential targets in cancer therapy. Here we report the down-regulation of activated VEGF receptor (VEGFR)-1/Flt-1 by endocytosis and proteolytic degradation. VEGF stimulation induced a ternary complex of Flt-1, c-Cbl, and CD2AP. Substitution of tyrosine 1333 in Flt-1 with phenylalanine (Y1333F) impaired its binding to c-Cbl. In a transient expression system, VEGF stimulated colocalization of Flt-1, CD2AP, and c-Cbl in endocytic vesicles. This colocalization was significantly impaired by an inhibitor of VEGFR kinase SU5416, the Y1333F mutation in Flt-1, or by a dominant negative form of CD2AP. In Flt-1-overexpressing NIH3T3 cells, expression of the wild-type CD2AP enhanced VEGF-stimulated internalization as well as ubiquitination of Flt-1 whereas that of a mutated form of either CD2AP or c-Cbl failed to do so. These results suggest that the c-Cbl/CD2AP complex binds to activated Flt-1 and plays a crucial role in its endocytosis and subsequent degradation.
Division of Genetics, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
Satsuki
S
Kobayashi
Asako
A
Sawano
Yoshihisa
Y
Nojima
Masabumi
M
Shibuya
Yoshiro
Y
Maru
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008099:Liver / Q000166:cytology; D046911:Macromolecular Substances; D051379:Mice; D010766:Phosphorylation; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D050721:Proto-Oncogene Proteins c-cbl; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000502:physiology; D014443:Tyrosine / Q000737:chemistry; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D018909:src Homology Domains
D033942:Adaptor Proteins, Vesicular Transport; D007211:Indoles; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D011758:Pyrroles; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; D042461:Vascular Endothelial Growth Factor A; D014443:Tyrosine; C116890:Semaxinib; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D040281:Vascular Endothelial Growth Factor Receptor-1; C067419:CBL protein, human; C493849:Cbl protein, mouse