RRC ID 67306
Author Walliser C, Tron K, Clauss K, Gutman O, Kobitski AY, Retlich M, Schade A, Röcker C, Henis YI, Nienhaus GU, Gierschik P.
Title Rac-mediated Stimulation of Phospholipase Cγ2 Amplifies B Cell Receptor-induced Calcium Signaling.
Journal J Biol Chem
Abstract The Rho GTPase Rac is crucially involved in controlling multiple B cell functions, including those regulated by the B cell receptor (BCR) through increased cytosolic Ca(2+). The underlying molecular mechanisms and their relevance to the functions of intact B cells have thus far remained unknown. We have previously shown that the activity of phospholipase Cγ2 (PLCγ2), a key constituent of the BCR signalosome, is stimulated by activated Rac through direct protein-protein interaction. Here, we use a Rac-resistant mutant of PLCγ2 to functionally reconstitute cultured PLCγ2-deficient DT40 B cells and to examine the effects of the Rac-PLCγ2 interaction on BCR-mediated changes of intracellular Ca(2+) and regulation of Ca(2+)-regulated and nuclear-factor-of-activated-T-cell-regulated gene transcription at the level of single, intact B cells. The results show that the functional Rac-PLCγ2 interaction causes marked increases in the following: (i) sensitivity of B cells to BCR ligation; (ii) BCR-mediated Ca(2+) release from intracellular stores; (iii) Ca(2+) entry from the extracellular compartment; and (iv) nuclear translocation of the Ca(2+)-regulated nuclear factor of activated T cells. Hence, Rac-mediated stimulation of PLCγ2 activity serves to amplify B cell receptor-induced Ca(2+) signaling.
Volume 290(28)
Pages 17056-72
Published 2015-7-10
DOI 10.1074/jbc.M115.645739
PII S0021-9258(20)35311-4
PMID 25903139
PMC PMC4498044
MeSH Active Transport, Cell Nucleus Amino Acid Substitution Animals Avian Proteins / chemistry Avian Proteins / genetics Avian Proteins / metabolism B-Lymphocytes / cytology B-Lymphocytes / immunology B-Lymphocytes / metabolism Calcium Signaling / physiology* Cell Line Chickens Humans Mice Models, Molecular Mutagenesis, Site-Directed NFATC Transcription Factors / metabolism Phospholipase C gamma / chemistry Phospholipase C gamma / genetics Phospholipase C gamma / metabolism* Protein Conformation Receptors, Antigen, B-Cell / metabolism* Recombinant Proteins / chemistry Recombinant Proteins / genetics Recombinant Proteins / metabolism rac GTP-Binding Proteins / chemistry rac GTP-Binding Proteins / genetics rac GTP-Binding Proteins / metabolism*
IF 4.238
Human and Animal Cells DT40(RCB1464) PLC-γ2^(-) DT40(RCB1469)