Expression of G protein alpha-subunits in XXXX parathyroid.

@entity141 @entity24585 @entity73280 @entity291
A G protein-coupled @entity141 -sensing receptor was recently cloned from @entity291 parathyroid and shown to mediate divalent cation regulation of @entity24585 secretion. To define which G proteins might be coupled to the @entity141 -sensing receptor in parathyroid cells, we determined which G protein alpha-subunit messenger RNAs (mRNAs) are expressed in the parathyroid. We also considered the possibility that a novel parathyroid-specific G alpha might be present. We, therefore, used the reverse transcription-polymerase chain reaction to study the expression of G alpha subunits in a @entity291 parathyroid mRNA preparation. Degenerate primers, corresponding to two regions conserved in every G alpha subunit, the G3 and G4 sequences, were used to amplify G alpha complementary DNA fragments that were subcloned and sequenced. We found that mRNAs corresponding to G alpha s, G alpha i2, @entity73280 , G alpha 12, and G alpha z are the predominant G alpha mRNAs expressed in the @entity291 parathyroid. No novel G alpha mRNA was identified. Northern blots confirmed the expression of the cloned G alpha subunits and showed lower expression of G alpha o and G alpha i1 mRNAs. Immunoblots confirmed abundant expression of G alpha s, G alpha i2, and @entity73280 and provided evidence for expression of G alpha i1 and G alpha i3, but not G alpha o. G alpha q mRNA was not identified by the degenerate primer reverse transcription-polymerase chain reaction strategy, but the immunoblot detected G alpha q protein, albeit at considerably lower levels than @entity73280 . The abundance of @entity73280 relative to G alpha q in @entity291 parathyroid is consistent with but does not prove a role for @entity73280 in coupling the @entity141 -sensing receptor to phospholipase C.
