Bradykinin (BK) B2 receptor signaling involves activation of phospholipase C (PLC). PLC activation by other receptors consists of either allosteric activation of PLCβ isoforms by G-proteins or tyrosine phosphorylation of PLCγ isoforms. Because the B2 receptor is a G-protein-coupled receptor, it has been assumed that the receptor signals through PLCβ. In the present study, however, we have found that BK stimulation of IP3 production and the Ca2+ signal in endothelial cells is dependent on tyrosine phosphorylation. Furthermore, stimulation of B2 receptors in these cells is accompanied by a transient tyrosine phosphorylation of PLCγ1. Phosphorylation is correlated with increased IP3 production and association of PLCγ1 with the C-terminal intracellular domain of the B2 receptor. The B2 receptor can thus physically associate with intracellular proteins other than G-proteins. Activation of PLCγ isoforms, rather than PLCβ isoforms, may, therefore, be primarily responsible for BK-stimulated IP3 generation in endothelial cells.
|Original language||English (US)|
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - May 8 1998|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology