Adipocyte plasma membranes contain two G i subtypes but are devoid of G o

Abstract

Antisera generated against synthetic peptides were used to identify G-protein α-subunits in plasma membranes from rat adipocytes. Applying the immunoblot technique, we detected two G s α-subunits of 42 and 43 kDa, corresponding to the two cholera toxin substrates, and two G i α-subunits of 40 and 41 kDa, corresponding to the two pertussis toxin substrates present in these membranes. The 40 kDa protein was tentatively identified as the G i2, α-subunit. A serum specific for the G o α-subunit failed to detect any immunoreactive protein. Thus plasma membranes of adipocytes possess two forms of G i but not G o.