Involvement of LAT, Gads, and Grb2 in compartmentation of SLP-76 to the plasma membrane.
B cell linker protein (BLNK) and Src homology 2 domain-containing leukocyte protein of 76 kD (SLP-76) are adaptor proteins required for B cell receptor (BCR) and T cell receptor function, respectively. Here, we show that expression of SLP-76 cannot reconstitute BCR function in Zap-70(+)BLNK(-) B cells. This could be attributable to inability of SLP-76 to be recruited into glycolipid-enriched microdomains (GEMs) after antigen receptor cross-linking. Supporting this idea, the BCR function was restored when a membrane-associated SLP-76 chimera was enforcedly localized to GEMs. Moreover, we demonstrate that addition of both linker for activation of T cells (LAT) and Grb2-related adaptor downstream of Shc (Gads) to SLP-76 allow SLP-76 to be recruited into GEMs, whereby the BCR function is reconstituted. The Gads function was able to be replaced by overexpression of Grb2. In contrast to SLP-76, BLNK did not require Grb2 families for its recruitment to GEMs. Hence, these data suggest a functional overlap between BLNK and SLP-76, while emphasizing the difference in requirement for additional adaptor molecules in their targeting to GEMs.
Ishiai
M
M
Department of Molecular Genetics, Institute for Liver Research, Kansai Medical University, Moriguchi 570-8506, Japan.
Kurosaki
M
M
Inabe
K
K
Chan
A C
AC
Sugamura
K
K
Kurosaki
T
T
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D002462:Cell Membrane / Q000276:immunology*; D002645:Chickens; D066246:ErbB Receptors / Q000502:physiology; D051380:GRB2 Adaptor Protein; D015723:Gene Library; D006801:Humans; D008565:Membrane Proteins; D010750:Phosphoproteins / Q000276:immunology / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011947:Receptors, Antigen, B-Cell / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction
D048868:Adaptor Proteins, Signal Transducing; C113939:B cell linker protein; D002352:Carrier Proteins; C409587:GRAP2 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C110810:LAT protein, human; D008565:Membrane Proteins; D010750:Phosphoproteins; D011506:Proteins; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; C092947:SLP-76 signal Transducing adaptor proteins; D066246:ErbB Receptors