A dynamic constitutive and inducible binding of c-Cbl by PLCgamma1 SH3 and SH2 domains (negatively) regulates antigen receptor-induced PLCgamma1 activation in lymphocytes.
We investigated the structural requirements for c-Cbl-mediated inhibition of Ag receptor-induced PLCgamma1 activation. Analysis of site-specific c-Cbl mutants indicated that tyrosine phosphorylation of c-Cbl was required for down-regulation of the PLCgamma1/Ca2+ pathway. Coprecipitation experiments indicated that c-Cbl and PLCgamma1 constitutively interact through a PLCgamma1 SH3 domain-dependent mechanism and that c-Cbl ... and PLCgamma1 can inducibly interact through the SH2(C) domain of PLCgamma1. Additional data indicate that the SH3 domain of PLCgamma1 binds to both canonical and noncanonical SH3 domain-binding sites in the proline-rich region of c-Cbl. Overexpression of c-Cbl in a PLCgamma-deficient B cell line, P10-14, stably reconstituted with wild-type PLCgamma1 led to a significant decrease in B cell receptor-induced NF-AT-dependent transcription, a PLCgamma- and Ca(2+)-dependent event. In contrast, c-Cbl overexpression in P10-14 cells reconstituted with a PLCgamma1 SH3 domain mutant had little effect on receptor-induced NF-AT activation. These data suggest that c-Cbl-mediated regulation of PLCgamma1 requires an interaction between c-Cbl and PLCgamma1 that is primarily mediated by the SH3 domain of PLCgamma1. The interaction of c-Cbl with PLCgamma1 may negatively effect events required for PLCgamma1 activation.
Mesh Terms:
Animals, Binding Sites, DNA-Binding Proteins, Down-Regulation, Feedback, Physiological, Humans, Jurkat Cells, Lymphocytes, Mutation, NFATC Transcription Factors, Nuclear Proteins, Phospholipase C gamma, Phosphorylation, Proline, Protein Binding, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-cbl, Receptors, Antigen, Transcription Factors, Transcriptional Activation, Type C Phospholipases, Tyrosine, Ubiquitin-Protein Ligases, src Homology Domains
Animals, Binding Sites, DNA-Binding Proteins, Down-Regulation, Feedback, Physiological, Humans, Jurkat Cells, Lymphocytes, Mutation, NFATC Transcription Factors, Nuclear Proteins, Phospholipase C gamma, Phosphorylation, Proline, Protein Binding, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-cbl, Receptors, Antigen, Transcription Factors, Transcriptional Activation, Type C Phospholipases, Tyrosine, Ubiquitin-Protein Ligases, src Homology Domains
Exp. Cell Res.
Date: Sep. 10, 2003
PubMed ID: 12941616
View in: Pubmed Google Scholar
Download Curated Data For This Publication
135658
Switch View:
- Interactions 5