TY - JOUR
T1 - Protein-tyrosine kinase and GTPase signals cooperate to phosphorylate and activate Wiskott-Aldrich syndrome protein (WASP)/neuronal WASP
AU - Torres, Eduardo
AU - Rosen, Michael K.
PY - 2006/2/10
Y1 - 2006/2/10
N2 - Protein-tyrosine kinases and Rho GTPases regulate many cellular processes, including the reorganization and dynamics of the actin cytoskeleton. The Wiskott-Aldrich syndrome protein (WASP) and its homolog neuronal WASP (N-WASP) are effectors of the Rho GTPase Cdc42 and provide a direct link between activated membrane receptors and the actin cytoskeleton. WASP and N-WASP are also regulated by a large number of other activators, including protein-tyrosine kinases, phosphoinositides, and Src homology 3-containing adaptor proteins, and can therefore serve as signal integrators inside cells. Here we show that Cdc42 and the Src family kinase Lck cooperate at two levels to enhance WASP activation. First, autoinhibition in N-WASP decreases the efficiency (k cat/Km) of phosphorylation and dephosphorylation of the GTPase binding domain by 30- and 40-fold, respectively, and this effect is largely reversed by Cdc42. Second, Cdc42 and the Src homology 3-Src homology 2 module of Lck cooperatively stimulate the activity of phosphorylated WASP, with coupling energy of ∼2.4 kcal/mol between the two activators. These combined effects provide mechanisms for high specificity in WASP activation by coincident GTPase and kinase signals.
AB - Protein-tyrosine kinases and Rho GTPases regulate many cellular processes, including the reorganization and dynamics of the actin cytoskeleton. The Wiskott-Aldrich syndrome protein (WASP) and its homolog neuronal WASP (N-WASP) are effectors of the Rho GTPase Cdc42 and provide a direct link between activated membrane receptors and the actin cytoskeleton. WASP and N-WASP are also regulated by a large number of other activators, including protein-tyrosine kinases, phosphoinositides, and Src homology 3-containing adaptor proteins, and can therefore serve as signal integrators inside cells. Here we show that Cdc42 and the Src family kinase Lck cooperate at two levels to enhance WASP activation. First, autoinhibition in N-WASP decreases the efficiency (k cat/Km) of phosphorylation and dephosphorylation of the GTPase binding domain by 30- and 40-fold, respectively, and this effect is largely reversed by Cdc42. Second, Cdc42 and the Src homology 3-Src homology 2 module of Lck cooperatively stimulate the activity of phosphorylated WASP, with coupling energy of ∼2.4 kcal/mol between the two activators. These combined effects provide mechanisms for high specificity in WASP activation by coincident GTPase and kinase signals.
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U2 - 10.1074/jbc.M509416200
DO - 10.1074/jbc.M509416200
M3 - Article
C2 - 16293614
AN - SCOPUS:33645643086
SN - 0021-9258
VL - 281
SP - 3513
EP - 3520
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 6
ER -