SH3P7 is a cytoskeleton adapter protein and is coupled to signal transduction from lymphocyte antigen receptors.
Lymphocytes respond to antigen receptor engagement with tyrosine phosphorylation of many cellular proteins, some of which have been identified and functionally characterized. Here we describe SH3P7, a novel substrate protein for Src and Syk family kinases. SH3P7 migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a 55-kDa protein that is preferentially expressed in brain, thymus, and spleen. It contains multiple amino acid sequence motifs, including two consensus tyrosine phosphorylation sites of the YXXP type and one SH3 domain. A region of sequence similarity, which we named SCAD, was found in SH3P7 and three actin-binding proteins. The SCAD region may represent a new type of protein-protein interaction domain that mediates binding to actin. Consistent with this possibility, SH3P7 colocalizes with actin filaments of the cytoskeleton. Altogether, our data implicate SH3P7 as an adapter protein which links antigen receptor signaling to components of the cytoskeleton.
Larbolette
O
O
Abteilung für Molekulare Immunologie, Institut für Biologie III, Albert-Ludwigs-Universität Freiburg, and Max-Planck-Institut für Immunbiologie, D-79108 Freiburg, Germany.
Wollscheid
B
B
Schweikert
J
J
Nielsen
P J
PJ
Wienands
J
J
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D008213:Lymphocyte Activation; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014443:Tyrosine / Q000737:chemistry; D018909:src Homology Domains; D019061:src-Family Kinases / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; C485512:Dbnl protein, mouse; D008840:Microfilament Proteins; D011947:Receptors, Antigen, B-Cell; D014443:Tyrosine; D019061:src-Family Kinases