Expression of G protein α-subunits in bovine parathyroid

Annie Varrault, Maria Sol Rodriguez Pena, Paul K. Goldsmith, Ambrish Mithal, Edward M. Brown, Allen M. Spiegel

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


A G protein-coupled Ca2+-sensing receptor was recently cloned from bovine parathyroid and shown to mediate divalent cation regulation of PTH secretion. To define which G proteins might be coupled to the Ca2+-sensing receptor in parathyroid cells, we determined which G protein α-subunit messenger RNAs (mRNAs) are expressed in the parathyroid. We also considered the possibility that a novel parathyroid-specific Gα might be present. We, therefore, used the reverse transcription-polymerase chain reaction to study the expression of Gα subunits in a bovine parathyroid mRNA preparation. Degenerate primers, corresponding to two regions conserved in every Gα subunit, the G3 and G4 sequences, were used to amplify Gα complementary DNA fragments that were subcloned and sequenced. We found that mRNAs corresponding to Gαs, Gαi2, Gα11, Gα12, and Gαz are the predominant Gα mRNAs expressed in the bovine parathyroid. No novel Gα mRNA was identified. Northern blots confirmed the expression of the cloned Gα subunits and showed lower expression of Gαo and Gαi1 mRNAs. Immunoblots confirmed abundant expression of Gαs, Gαi2, and Gα11 and provided evidence for expression of Gαi1 and Gαi3, but not Gαo. Gαq mRNA was not identified by the degenerate primer reverse transcription-polymerase chain reaction strategy, but the immunoblot detected Gαq protein, albeit at considerably lower levels than Gα11. The abundance of Gα11 relative to Gαq in bovine parathyroid is consistent with but does not prove a role for Gα11 in coupling the Ca2+- sensing receptor to phospholipase C.

Original languageEnglish (US)
Pages (from-to)4390-4396
Number of pages7
Issue number10
StatePublished - Oct 1995
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology


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