Cooperative interactions at the SLP-76 complex are critical for actin polymerization.
T-cell antigen receptor (TCR) engagement induces formation of multi-protein signalling complexes essential for regulating T-cell functions. Generation of a complex of SLP-76, Nck and VAV1 is crucial for regulation of the actin machinery. We define the composition, stoichiometry and specificity of interactions in the SLP-76, Nck and VAV1 complex. Our data reveal that this complex can contain one SLP-76 molecule, two Nck and two VAV1 molecules. A direct interaction between Nck and VAV1 is mediated by binding between the C-terminal SH3 domain of Nck and the VAV1 N-terminal SH3 domain. Disruption of the VAV1:Nck interaction deleteriously affected actin polymerization. These novel findings shed new light on the mechanism of actin polymerization after T-cell activation.
Barda-Saad
Mira
M
Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel. bardasm@mail.biu.ac.il
Shirasu
Naoto
N
Pauker
Maor H
MH
Hassan
Nirit
N
Perl
Orly
O
Balbo
Andrea
A
Yamaguchi
Hiroshi
H
Houtman
Jon C D
JC
Appella
Ettore
E
Schuck
Peter
P
Samelson
Lawrence E
LE
D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D018909:src Homology Domains
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C078332:Nck protein; D015513:Oncogene Proteins; D010750:Phosphoproteins; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; C092947:SLP-76 signal Transducing adaptor proteins; C496618:VAV1 protein, human