The G alpha q and G alpha 11 proteins couple the thyrotropin-releasing hormone receptor to phospholipase C in GH3 rat pituitary cells
| Autor: | Anna M. Aragay, Arieh Katz, Melvin I. Simon |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1992 |
| Předmět: |
G protein-coupled receptor kinase
endocrine system G protein Interleukin 5 receptor alpha subunit Cell Biology Biology Biochemistry Interleukin 10 receptor alpha subunit G beta-gamma complex Thyrotropin-releasing hormone receptor G12/G13 alpha subunits Molecular Biology Caltech Library Services G alpha subunit |
| Popis: | Thyrotropin-releasing hormone stimulates the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) in GH3 cell membranes. The stimulation of the phosphoinositide phospholipase C (PI/PLC) activity can be blocked by incubation of GH3 membranes with polyclonal antibodies directed against a peptide derived from the C-terminal region of G alpha q and G alpha 11. Antibodies directed against the C- terminal region of other G alpha-subunits had no detectable effect. The inhibition was specific since addition of the peptide that was used to prepare the antibody completely reversed the inhibition. Further evidence for the coupling of the TRH receptor to G alpha q or G alpha 11 comes from a reconstitution experiment in which human embryonic kidney cells were transiently transfected with cDNAs corresponding to the TRH receptor, G alpha q or G alpha 11. The PIP2 hydrolysis detected with membranes from cells that over-expressed the TRH receptor alone was low, however, co-expression with the G alpha q or G alpha 11 subunits produced a synergistic stimulation of PI-PLC activity. In contrast, co-expression of these alpha-subunits with the M2 muscarinic acetylcholine receptor induced a weak stimulation of PIP2 hydrolysis. The results presented here suggest that the TRH-dependent stimulation of PI-PLC in GH3 cells is mediated through the G-protein alpha- subunits, G alpha q and/or G alpha 11. |
| Databáze: | OpenAIRE |
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