4k44 | pdb_00004k44
Auto-inhibition and phosphorylation-induced activation of PLC-gamma isozymes
Structural highlights
Function[PLCG1_RAT] Mediates the production of the second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). Plays an important role in the regulation of intracellular signaling cascades. Becomes activated in response to ligand-mediated activation of receptor-type tyrosine kinases, such as PDGFRA, PDGFRB, FGFR1, FGFR2, FGFR3 and FGFR4. Plays a role in actin reorganization and cell migration (By similarity). Publication Abstract from PubMedMultiple extracellular stimuli, such as growth factors and antigens, initiate signaling cascades through tyrosine phosphorylation and activation of phospholipase C (PLC)-gamma isozymes. Like most other PLCs, PLC-gamma1 is basally auto-inhibited by its X-Y linker, which separates the X- and Y-boxes of the catalytic core. The C-terminal SH2 (cSH2) domain within the X-Y linker is the critical determinant for auto-inhibition of phospholipase activity. Release of auto-inhibition requires an intramolecular interaction between the cSH2 domain and a phosphorylated tyrosine, Tyr783, also located within the X-Y linker. The molecular mechanisms that mediate auto-inhibition and phosphorylation-induced activation have not been defined. Here, we describe structures of the cSH2 domain both alone and bound to a PLC-gamma1 peptide encompassing phosphorylated Tyr783. The cSH2 domain remains largely unaltered by peptide engagement. Point mutations in the cSH2 domain located at the interface with the peptide were sufficient to constitutively activate PLC-gamma1 suggesting that peptide engagement directly interferes with the capacity of the cSH2 domain to block the lipase active site. This idea is supported by mutations in a complimentary surface of the catalytic core that also enhanced phospholipase activity. Auto-inhibition and phosphorylation-induced activation of PLC-gamma isozymes.,Hajicek N, Charpentier TH, Rush JR, Harden TK, Sondek JE Biochemistry. 2013 Jun 18. PMID:23777354[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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