Modulation of intracellular Ca(2+) via alpha(1B)-adrenoreceptor signaling molecules, G alpha(h) (transglutaminase II) and phospholipase C-delta 1.
We characterized the alpha(1B)-adrenoreceptor (alpha(1B)-AR)-mediated intracellular Ca(2+) signaling involving G alpha(h) (transglutaminase II, TGII) and phospholipase C (PLC)-delta 1 using DDT1-MF2 cell. Expression of wild-type TGII and a TGII mutant lacking transglutaminase activity resulted in significant increases in a rapid peak and a sustained level of intracellular Ca(2+) concentration ([Ca(2+)](i)) in response to activation of the alpha(1B)-AR. Expression of a TGII mutant lacking the interaction with the receptor or PLC-delta 1 substantially reduced both the peak and sustained levels of [Ca(2+)](i). Expression of TGII mutants lacking the interaction with PLC-delta 1 resulted in a reduced capacitative Ca(2+) entry. Reduced expression of PLC-delta 1 displayed a transient elevation of [Ca(2+)](i) and a reduction in capacitative Ca(2+) entry. Expression of the C2-domain of PLC-delta 1, which contains the TGII interaction site, resulted in reduction of the alpha(1B)-AR-evoked peak increase in [Ca(2+)](i), while the sustained elevation in [Ca(2+)](i) and capacitative Ca(2+) entry remained unchanged. These findings demonstrate that stimulation of PLC-delta 1 via coupling of the alpha(1B)-AR with TGII evokes both Ca(2+) release and capacitative Ca(2+) entry and that capacitative Ca(2+) entry is mediated by the interaction of TGII with PLC-delta 1.
Kang
Sung Koo
SK
Department of Molecular Cardiology, The Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Kim
Dae Kyong
DK
Damron
Derek S
DS
Baek
Kwang Jin
KJ
Im
Mie-Jae
MJ
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006224:Cricetinae; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D016296:Mutagenesis; D054803:Phospholipase C delta; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D007527:Isoenzymes; D018340:Receptors, Adrenergic, alpha-1; D011994:Recombinant Proteins; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D010738:Type C Phospholipases; D054803:Phospholipase C delta; D019204:GTP-Binding Proteins; D002118:Calcium