Table 1. Allele-specific suppression of S177 and E152 mutations but not the weaver mutation by N94 mutations.
| N94Y | N94F | N94H | N94M | N94D | |
|---|---|---|---|---|---|
| S177D | + | + | - | - | - |
| S177G | - | + | + | - | - |
| S177F | + | + | + | - | - |
| S177P | - | - | - | - | - |
| S177Y | + | + | + | - | - |
| S177N | + | + | + | - | - |
| S177H | - | - | - | - | - |
| E152T | - | + | - | - | - |
| E152V | - | - | - | - | - |
| E152A | + | + | + | - | - |
| E152H | - | - | - | - | - |
| E152G | + | + | + | - | - |
| weaver | - | - | - | - | - |
Eight substitutions at S177 in M2 (D, G, F, W, P, Y, N, and H), five substitutions at E152 in the pore helix (T, V, A, H, and G), and the G156S identified in the pore loop of the gene encoding for the GIRK2 channel of the weaver mouse were found to confer Na+ permeability to GIRK2 channels (Fig. 10 and Table 3). These mutations (rows 2-14) were combined with five substitutions of N94 in M1 (Y, F, H, M, and D, columns 2-6), and the double-mutant GIRK2 channels were tested for their ability to rescue yeast growth on 0.5 mM K+ medium.