Adipocyte plasma membranes contain two Gi subtypes but are devoid of Go

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.