TABLE I.
Effect of Sgk1 and CAP1 on ENaC-mediated Sodium Current (INa) and Cell Surface Expression (N) Measured by Monoclonal Antibody Binding to Flagged αβγENaC
| Before trypsin treatment | After trypsin treatment | ||||||
|---|---|---|---|---|---|---|---|
| cRNA injection | n (oocyte) | N (f mole/oocyte) | INa | INa/N | INa | INa/N | INa/N − tryp/INa/N + tryp |
| a | b | c | d | e | e/c | ||
| μA/oocyte | μA/f mole | μA/oocyte | μA/f mole | ||||
| ENaC + H2O | 40 | 0.085 ± 0.007 | 1.1 ± 0.2 | 14.2 ± 1.0 | 6.2 ± 1.0 | 84.1 ± 12.3 | 5.9 (P < 0.01) |
| ENaC + mCAP1 | 35 | 0.085 ± 0.010 | 11.9 ± 1.5 | 182.6 ± 24.3 | 11.4 ± 1.5 | 175.9 ± 23.3 | 1.0 (ns) |
| ENaC + Sgk1 | 31 | 0.139 ± 0.014 | 2.7 ± 0.4 | 21.7 ± 2.9 | 12.0 ± 1.6 | 102.9 ± 14.2 | 4.7 (P < 0.01) |
| ENaC + Sgk1 + mCAP1 | 26 | 0.186 ± 0.015 | 24.5 ± 1.8 | 162.8 ± 21.2 | 24.4 ± 1.7 | 149.3 ± 14.1 | 0.9 (ns) |
INa and N were measured in the same oocyte as described in materials and methods. 26–40 oocytes from a minimum of 5 different batches were measured for each experimental condition.
t test results for N: control vs. CAP1, P < 0.9; control vs. Sgk1, P < 0.001; control vs. Sgk1 + mCAP1, P < 0.001; mCAP1 vs. Sgk1, P < 0.001; mCAP1 vs. Sgk1 + mCAP1, P < 0.001; Sgk1 vs. Sgk1 + mCAP1, P < 0.02.
t test results for INa: control vs. CAP1, P < 0.001; control vs. Sgk1, P < 0.001; control vs. Sgk1 + mCAP1, P < 0.001; mCAP1 vs. Sgk1, P < 0.001; mCAP1 vs. Sgk1 + mCAP1, P < 0.001; Sgk1 vs. Sgk1 + mCAP1, P < 0.001.
t test results for INa/N: control vs. CAP1, P < 0.001; control vs. Sgk1, P < 0.03; control vs. Sgk1 + mCAP1, P < 0.001; mCAP1 vs. Sgk1, P < 0.001; mCAP1 vs. Sgk1 + mCAP1, P < 0.55; Sgk1 vs. Sgk1 + mCAP1, P < 0.001.