Figure 6.

Western blot of oocyte membrane protein preparations assayed with anti-GABA_C ρ1 antibody. Membrane preparations were obtained from oocytes expressing the following ρ1 GABA_C receptors: Lane 1: nonexpressing control oocytes. Lane 2: wild-type ρ1 GABA_C. Lane 3: R158A mutant. Lane 4: R158D mutant. Lane 5: D204A mutant. Lane 6: D204R mutant. Lane 7: R158D–D204R double mutant. Mutations at D204 result in the receptors with molecular weights similar to the native ρ1 subunits, while R158D mutation yields partially degraded receptors (band at ∼24 kDa, Lane 4), possibly as a result of misfolding. Double mutant R158D–D204R (Lane 7) contains only ∼55 kDa and ∼40 kDa products, implying that receptor subunit folding is rescued by the additional mutation at Position 204.