TY - JOUR
T1 - Cbl-mediated ubiquitinylation and negative regulation of Vav
AU - Miura-Shimura, Yuko
AU - Duan, Lei
AU - Rao, Navin L.
AU - Reddi, Alagarsamy L.
AU - Shimura, Hideki
AU - Rottapel, Rob
AU - Druker, Brain J.
AU - Tsygankov, Alexander
AU - Band, Vimla
AU - Band, Hamid
PY - 2003/10/3
Y1 - 2003/10/3
N2 - The Cbl ubiquitin ligase has emerged as a negative regulator of receptor and non-receptor tyrosine kinases. Cbl is known to associate with the proto-oncogene product Vav, a hematopoietic-restricted Rac guanine nucleotide exchange factor, but the consequences of this interaction remain to be elucidated. Using immortalized T cell lines from Cbl+/+ and Cbl -/- mice, and transfection analyses in 293T cells, we demonstrate that Vav undergoes Cbl-dependent ubiquitinylation under conditions that promote Cbl and Vav phosphorylation. Interaction with Cbl also induced the loss of phosphorylated Vav. In addition, we show that an activated Vav mutant (Vav-Y174F) is more sensitive to Cbl-dependent ubiquitinylation. We demonstrate that the Cbl-dependent ubiquitinylation of Vav requires Cbl/Vav association through phosphorylated Tyr-700 on Cbl, and also requires an intact Cbl RING finger domain. Finally, using transfection analyses in the Jurkat T cell line, we show that Cbl, but not its ubiquitin ligase mutant, can inhibit Vav-dependent signaling. Thus, our findings strongly support the role of Cbl, via its ubiquitin ligase activity, as a negative regulator of activated Vav.
AB - The Cbl ubiquitin ligase has emerged as a negative regulator of receptor and non-receptor tyrosine kinases. Cbl is known to associate with the proto-oncogene product Vav, a hematopoietic-restricted Rac guanine nucleotide exchange factor, but the consequences of this interaction remain to be elucidated. Using immortalized T cell lines from Cbl+/+ and Cbl -/- mice, and transfection analyses in 293T cells, we demonstrate that Vav undergoes Cbl-dependent ubiquitinylation under conditions that promote Cbl and Vav phosphorylation. Interaction with Cbl also induced the loss of phosphorylated Vav. In addition, we show that an activated Vav mutant (Vav-Y174F) is more sensitive to Cbl-dependent ubiquitinylation. We demonstrate that the Cbl-dependent ubiquitinylation of Vav requires Cbl/Vav association through phosphorylated Tyr-700 on Cbl, and also requires an intact Cbl RING finger domain. Finally, using transfection analyses in the Jurkat T cell line, we show that Cbl, but not its ubiquitin ligase mutant, can inhibit Vav-dependent signaling. Thus, our findings strongly support the role of Cbl, via its ubiquitin ligase activity, as a negative regulator of activated Vav.
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U2 - 10.1074/jbc.M305656200
DO - 10.1074/jbc.M305656200
M3 - Article
C2 - 12881521
AN - SCOPUS:0141866846
SN - 0021-9258
VL - 278
SP - 38495
EP - 38504
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 40
ER -