Regulation of PDGF-beta receptor-operated Ca2+ channels by phospholipase C-gamma 1 in glomerular mesangial cells.
Platelet-derived growth factor (PDGF)-induced Ca2+ signaling mechanisms were examined in cultured rat glomerular mesangial cells. PDGF-BB stimulated the tyrosine phosphorylation of phospholipase C (PLC)-gamma 1, the formation of a PLC-gamma 1/PDGF-beta receptor membrane complex, and the generation of intracellular inositol 1,4,5-trisphosphate (IP3). Preincubation with a tyrosine kinase inhibitor (genistein) abolished these PDGF-induced responses. Activation of 1-pS Ca2+ channels in cell-attached patches by intrapipette PDGF-BB was also abolished by tyrosine kinase inhibition. In the absence of PDGF-BB, channels were activated in cell-attached patches exposed to intrapipette thapsigargin (IP3-independent releaser of intracellular Ca2+ stores) and in excised inside-out patches exposed to increasing "cytoplasmic" Ca2+ (10(-8) to 10(-6) M). In cell-attached patches, channel activation by PDGF-BB was abolished when extracellular Ca2+ was < 1 mM. In glomerular mesangial cells 1) PDGF-BB stimulates tyrosine phosphorylation of PLC-gamma 1, PDGF-beta receptor/PLC-gamma 1 membrane complex formation, IP3 production, and 1-pS Ca2+ channel activity; 2) all four PDGF-induced responses are abolished by tyrosine kinase inhibition; 3) PDGF receptor-operated Ca2+ channels are sensitive to both intra- and extracellular Ca2+.
Ma
H
H
Renal Division, Emory University School of Medicine, Atlanta, Georgia, USA.
Matsunaga
H
H
Li
B
B
Marrero
M B
MB
Ling
B N
BN
D000818:Animals; D000077214:Becaplermin; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D005110:Extracellular Space / Q000378:metabolism; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D007527:Isoenzymes / Q000502:physiology*; D008297:Male; D018408:Patch-Clamp Techniques; D051966:Phospholipase C gamma; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism / Q000502:physiology*; D010738:Type C Phospholipases / Q000502:physiology*
D015220:Calcium Channels; D007527:Isoenzymes; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D015544:Inositol 1,4,5-Trisphosphate; D011505:Protein-Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor; D011493:Protein Kinase C; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium