Phospholipase C-delta1 is activated by capacitative calcium entry that follows phospholipase C-beta activation upon bradykinin stimulation

J Biol Chem. 1999 Sep 10;274(37):26127-34. doi: 10.1074/jbc.274.37.26127.

Abstract

To characterize the regulatory mechanism of phospholipase C-delta1 (PLC-delta1) in the bradykinin (BK) receptor-mediated signaling pathway, we used a clone of PC12 cells, which stably overexpress PLC-delta1 (PC12-D1). Stimulation with BK induced a significantly higher Ca(2+) elevation and inositol 1,4,5-trisphosphate (IP(3)) production with a much lower half-maximal effective concentration (EC(50)) of BK in PC12-D1 cells than in wild type (PC12-W) or vector-transfected (PC12-V) cells. However, BK-induced intracellular Ca(2+) release and IP(3) generation was similar between PC12-V and PC12-D1 cells in the absence of extracellular Ca(2+), suggesting that the availability of extracellular Ca(2+) is essential to the activation of PLC-delta1. When PC12-D1 cells were treated with agents that induce Ca(2+) influx, more IP(3) was produced, suggesting that the Ca(2+) entry induces IP(3) production in PC12-D1 cells. Furthermore, the additional IP(3) production after BK-induced capacitative calcium entry was detected in PC12-D1 cells, suggesting that PLC-delta1 is mainly activated by capacitative calcium entry. When cells were stimulated with BK in the presence of extracellular Ca(2+), [(3)H]norepinephrine secretion was much greater from PC12-D1 cells than from PC12-V cells. Our results suggest that PLC-delta1 is activated by capacitative calcium entry following the activation of PLC-beta, additively inducing IP(3) production and Ca(2+) rise in BK-stimulated PC12 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bradykinin / pharmacology*
  • Calcium / metabolism*
  • Enzyme Activation
  • GTP-Binding Proteins / metabolism
  • Inositol 1,4,5-Trisphosphate / biosynthesis
  • Isoenzymes / metabolism*
  • Norepinephrine / metabolism
  • PC12 Cells
  • Phospholipase C beta
  • Phospholipase C delta
  • Rats
  • Type C Phospholipases / metabolism*

Substances

  • Isoenzymes
  • Inositol 1,4,5-Trisphosphate
  • Type C Phospholipases
  • Phospholipase C beta
  • Phospholipase C delta
  • Plcd1 protein, rat
  • GTP-Binding Proteins
  • Bradykinin
  • Calcium
  • Norepinephrine