B cell receptor signaling involves physical and functional association of FAK with Lyn and IgM.
B cell receptor (BCR) stimulation induces phosphorylation of a number of proteins, leading to functional activation of B lymphocytes. Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase, involved in a variety of signaling pathways. In this study, we show that FAK is tyrosine-phosphorylated and activated following BCR stimulation. We also demonstrate constitutive association of FAK with the Src-family kinase Lyn and with components of the BCR. Association of Lyn with FAK which was not correlated with BCR-induced activation of both kinases, appeared to be mediated via the binding of Lyn to the COOH-terminal part of the FAK molecule. Our results indicate that FAK is a component of the BCR complex and that it participates in BCR signaling.
Mlinaric-Rascan
I
I
Department of Oncology, Institute of Medical Science, University of Tokyo, Japan.
Yamamoto
T
T
D000818:Animals; D000936:Antigen-Antibody Complex / Q000378:metabolism; D001402:B-Lymphocytes / Q000201:enzymology / Q000502:physiology*; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology*; D051379:Mice; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000502:physiology*; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D000936:Antigen-Antibody Complex; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases