Phospholipase C-beta3 mediates the thrombin-induced Ca2+ response in glial cells.
Phospholipase C-beta (PLC-beta) hydrolyses phosphatidylinositol 4,5-bisphosphate and generates inositol 1,4,5-trisphosphate in response to activation of various G protein-coupled receptors (GPCRs). Using glial cells from knock-out mice lacking either PLC-beta1 [PLC-beta1 (-/-)] or PLC-beta3 [PLC-beta3 (-/-)], we examined which isotype of PLC-beta participated in the cellular signaling events triggered by thrombin. Generation of inositol phosphates (IPs) was enhanced by thrombin in PLC-beta1 (-/-) cells, but was negligible in PLC-beta3 (-/-) cells. Expression of PLC-beta3 in PLC-beta3 (-/-) cells resulted in an increase in pertussis toxin (PTx)-sensitive IPs in response to thrombin as well as to PAR1-specific peptide, while expression of PLC-beta1 in PLC-beta1 (-/-) cells did not have any effect on IP generation. The thrombin-induced [Ca2+]i increase was delayed and attenuated in PLC-beta3 (-/-) cells, but normal in PLC-beta1 (-/-) cells. Pertussis toxin evoked a delayed [Ca2+]i increase in PLC-beta3 (-/-) cells as well as in PLC-beta1 (-/-) cells. These results suggest that activation of PLC-beta3 by pertussis toxin-sensitive G proteins is responsible for the transient [Ca2+]i increase in response to thrombin, whereas the delayed [Ca2+]i increase may be due to activation of some other PLC, such as PLC-beta4, acting via PTx-insensitive G proteins.
Hwang
Jong-Ik
JI
Department of Life Science, Division of Molecular and Life Science Pohang University of Science and Technology, Pohang 790-784, Korea.
Shin
Kum-Joo
KJ
Oh
Yong-Seok
YS
Choi
Jung-Woong
JW
Lee
Zee-Won
ZW
Kim
Daesoo
D
Ha
Kwon-Soo
KS
Shin
Hee-Sup
HS
Ryu
Sung Ho
SH
Suh
Pann-Ghill
PG
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D004963:Estrenes / Q000494:pharmacology; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D007295:Inositol Phosphates / Q000096:biosynthesis; D007527:Isoenzymes / Q000096:biosynthesis / Q000172:deficiency / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin / Q000494:pharmacology; D054799:Phospholipase C beta; D011760:Pyrrolidinones / Q000494:pharmacology; D044463:Receptor, PAR-1 / Q000096:biosynthesis; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000502:physiology*; D010738:Type C Phospholipases / Q000172:deficiency / Q000502:physiology*
D004963:Estrenes; D007295:Inositol Phosphates; D007527:Isoenzymes; D011760:Pyrrolidinones; D044463:Receptor, PAR-1; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D054799:Phospholipase C beta; C518034:Plcb1 protein, mouse; C518040:Plcb3 protein, mouse; C518043:Plcb4 protein, mouse; D013917:Thrombin; D020962:Heterotrimeric GTP-Binding Proteins; D002118:Calcium