TY - JOUR
T1 - Vav1 acidic region tyrosine 174 is required for the formation of T cell receptor-induced microclusters and is essential in T cell development and activation
AU - Miletic, Ana V.
AU - Sakata-Sogawa, Kumiko
AU - Hiroshima, Michio
AU - Hamann, Michael J.
AU - Gomez, Timothy S.
AU - Ota, Naruhisa
AU - Kloeppel, Tracie
AU - Kanagawa, Osami
AU - Tokunaga, Makio
AU - Billadeau, Daniel D.
AU - Swat, Wojciech
PY - 2006/12/15
Y1 - 2006/12/15
N2 - Vav proteins are multidomain signaling molecules critical for mediating signals downstream of several surface receptors, including the antigen receptors of T and B lymphocytes. The catalytic guanine nucleotide exchange factor (GEF) activity of the Vav Dbl homology (DH) domain is thought to be controlled by an intramolecular autoinhibitory mechanism involving an N-terminal extension and phosphorylation of tyrosine residues in the acidic region (AC). Here, we report that the sequences surrounding the Vav1 AC: Tyr142, Tyr 160, and Tyr174 are evolutionarily conserved, conform to consensus SH2 domain binding motifs, and bind several proteins implicated in TCR signaling, including Lck, PI3K p85α, and PLCγ1, through direct interactions with their SH2 domains. In addition, the AC tyrosines regulate tyrosine phosphorylation of Vav1. We also show that Tyr174 is required for the maintenance of TCR-signaling microclusters and for normal T cell development and activation. In this regard, our data demonstrate that while Vav1 Tyr174 is essential for maintaining the inhibitory constraint of the DH domain in both developing and mature T cells, constitutively activated Vav GEF disrupts TCR-signaling microclusters and leads to defective T cell development and proliferation.
AB - Vav proteins are multidomain signaling molecules critical for mediating signals downstream of several surface receptors, including the antigen receptors of T and B lymphocytes. The catalytic guanine nucleotide exchange factor (GEF) activity of the Vav Dbl homology (DH) domain is thought to be controlled by an intramolecular autoinhibitory mechanism involving an N-terminal extension and phosphorylation of tyrosine residues in the acidic region (AC). Here, we report that the sequences surrounding the Vav1 AC: Tyr142, Tyr 160, and Tyr174 are evolutionarily conserved, conform to consensus SH2 domain binding motifs, and bind several proteins implicated in TCR signaling, including Lck, PI3K p85α, and PLCγ1, through direct interactions with their SH2 domains. In addition, the AC tyrosines regulate tyrosine phosphorylation of Vav1. We also show that Tyr174 is required for the maintenance of TCR-signaling microclusters and for normal T cell development and activation. In this regard, our data demonstrate that while Vav1 Tyr174 is essential for maintaining the inhibitory constraint of the DH domain in both developing and mature T cells, constitutively activated Vav GEF disrupts TCR-signaling microclusters and leads to defective T cell development and proliferation.
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U2 - 10.1074/jbc.M608913200
DO - 10.1074/jbc.M608913200
M3 - Article
C2 - 17050525
AN - SCOPUS:33845981504
SN - 0021-9258
VL - 281
SP - 38257
EP - 38265
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 50
ER -