Promiscuous Coupling of Receptors to Gq Class α Subunits and Effector Proteins in Pancreatic and Submandibular Gland Cells

Mice with deficiencies in one or more Gq class α subunit genes were used to examine the role of the α subunit in regulating Ca2+ signaling in pancreatic and submandibular gland cells. Western blot analysis showed that these cells express three of the four Gq class subunits, Gαq, Gα11, and Gα14 but n...

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Bibliographic Details
Published in:The Journal of biological chemistry 1998-10, Vol.273 (42), p.27275-27279
Main Authors: Xu, Xin, Croy, Jennifer T., Zeng, Weizhang, Zhao, Liping, Davignon, Isabelle, Popov, Serguei, Yu, Kan, Jiang, Huiping, Offermanns, Stefan, Muallem, Shmuel, Wilkie, Thomas M.
Format: Article
Language:English
Subjects:
Animals
Calcium - metabolism
Calcium Signaling
Carbachol - pharmacology
Epinephrine - pharmacology
GTP-Binding Proteins - deficiency
GTP-Binding Proteins - metabolism
Mice
Mice, Knockout
Pancreas - cytology
Pancreas - metabolism
Protein Binding
Receptor, Muscarinic M3
Receptors, Adrenergic, alpha-1
Receptors, Bombesin
Receptors, Cholecystokinin
Receptors, Muscarinic
Receptors, Neuropeptide - agonists
Receptors, Neuropeptide - metabolism
Submandibular Gland - cytology
Submandibular Gland - metabolism
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Summary:Mice with deficiencies in one or more Gq class α subunit genes were used to examine the role of the α subunit in regulating Ca2+ signaling in pancreatic and submandibular gland cells. Western blot analysis showed that these cells express three of the four Gq class subunits, Gαq, Gα11, and Gα14 but not Gα15. Surprisingly, all parameters of Ca2+signaling were identical in cells from wild type and four lines of mutant mice: 1) Gα11−/−, 2) Gα11−/−/Gα14−/−, 3) Gα14−/−/Gα15−/−, and 4) Gαq−/−/Gα15−/−. These parameters included the Kapp for several Gq class coupled receptors, induction of [Ca2+]ioscillations by weak stimulation, and a biphasic [Ca2+]i response by strong stimulation. Furthermore, Ca2+ release from internal stores and Ca2+ entry were not affected in cells from any of the mutant mice. We conclude that Gαq, Gα11, and Gα14 promiscuously couple several receptors (m3 muscarinic, bombesin, cholecystokinin, and α1 adrenergic) to effector proteins that activate both Ca2+ release from internal stores and Ca2+ entry.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.42.27275