title: Association of protein kinase C-delta with the B cell antigen receptor complex.
abstract: Protein kinase C (PKC)-delta is a diacylglycerol-dependent, calcium-independent novel PKC isoform and has been demonstrated to exert negative regulatory functions in B lymphocytes as well as in mast cells. Whereas in mast cells PKC-delta functionally interacts with the high-affinity receptor for IgE, FcepsilonR1, no such association has been described for the B cell antigen receptor (BCR). In this report, for the first time, we demonstrate the interaction of PKC-delta with different classes of BCR by means of affinity purification and native protein complex analysis. Using a C-terminally truncated Ig-alpha as well as non-phosphorylated and phosphorylated peptides representing C-terminal regions of Ig-alpha, the dependence of this BCR/PKC-delta interaction on tyrosine-phosphorylated Ig-alpha is shown. Finally, splenocytes from PKC-delta-deficient mice are found to exert reduced phosphorylation of PKD (a.k.a. PKC-mu) in response to BCR engagement, suggesting the early, membrane-proximal activation of an attenuating kinase complex including PKC-delta and PKD.
authors.affiliation: Department of Molecular Immunology, Biology III, University of Freiburg and Max-Planck-Institute for Immunobiology, 79108 Freiburg, Germany.
authors.forename: Catrin
authors.initials: C
authors.lastname: Pracht
authors.forename: Susana
authors.initials: S
authors.lastname: Minguet
authors.forename: Michael
authors.initials: M
authors.lastname: Leitges
authors.forename: Michael
authors.initials: M
authors.lastname: Reth
authors.forename: Michael
authors.initials: M
authors.lastname: Huber
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000172:deficiency / Q000302:isolation & purification / Q000378:metabolism*; D011947:Receptors, Antigen, B-Cell / Q000145:classification / Q000378:metabolism*
chemical_list: D010455:Peptides; D011947:Receptors, Antigen, B-Cell; D019000:Phosphotyrosine; C089212:protein kinase D; D011493:Protein Kinase C; D051745:Protein Kinase C-delta