Autor: |
Lock P; Cell Signaling Laboratory, Department of Surgery, University of Melbourne, Royal Melbourne Hospital, Parkville 3050, Australia. petelock@unimelb.edu.au, I ST, Straffon AF, Schieb H, Hovens CM, Stylli SS |
Jazyk: |
angličtina |
Zdroj: |
Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2006 Dec 29; Vol. 351 (4), pp. 1018-23. Date of Electronic Publication: 2006 Nov 03. |
DOI: |
10.1016/j.bbrc.2006.10.150 |
Abstrakt: |
Spred proteins modulate growth factor receptor signaling by inhibiting the Ras-MAPK cascade. Here, we show that Spred-1, Spred-2, and Spred-3 are ubiquitinated in HEK293T cells stimulated with epidermal growth factor (EGF) or pervanadate. Spred-2 tyrosines Y228 and/or Y231 in the Kit binding domain were identified as putative phosphorylation site(s) critical for Spred-2 ubiquitination. Depletion of Cbl and Cbl-b E3 ubiquitin ligases by RNA interference, or overexpression of a Cbl dominant inhibitory mutant (Cbl-N), inhibited Spred-2 ubiquitination, while conversely, wild type Cbl enhanced Spred-2 ubiquitination. Interaction of Spred-2 with Cbl-N was detectable by co-immunoprecipitation and required the Cbl SH2 domain and Spred-2 Y228 and Y231 residues. Studies on endogenous Spred-2 in ME4405 melanoma cells showed that pervanadate induced Spred-2 ubiquitination and a marked reduction in Spred-2 steady-state levels that was partially blocked by the proteasomal inhibitor, MG-132. These results suggest a role for Spred-2 tyrosine phosphorylation and ubiquitination in controlling Spred-2 expression levels. |
Databáze: |
MEDLINE |
Externí odkaz: |
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