TABLE 2

Mutant protein biogenesis and activity

Surface expression (% of wild-type channel level)MgADP stimulation (% current in 0.1 mmol/L ATP plus 0.5 mmol/L ADP)Diazoxide stimulation (% current in 0.1 mmol/L ATP plus 0.2 mmol/L diazoxide)
Mutation
1) Q474R119.12 ± 13.873.16 ± 1.34 (n = 3)2.03 ± 0.77 (n = 3)
2) A478D83.67 ± 5.330.69 ± 0.27 (n = 6)3.14 ± 1.37 (n = 3)
3) V715A83.00 ± 5.290.53 ± 0.28 (n = 3)1.73 ± 0.53 (n = 4)
4) V715G96.33 ± 3.180.28 ± 0.16 (n = 3)2.35 ± 1.99 (n = 3)
5) G716D66.67 ± 5.242.39 ± 1.90 (n = 6)2.37 ± 1.32 (n = 4)
6) T888P54.33 ± 5.330.38 ± 0.30 (n = 3)1.30 ± 0.44 (n = 3)
7) G1384E101.80 ± 8.500.17 ± 0.09 (n = 4)1.64 ± 0.49 (n = 4)
8) S1387F83.91 ± 5.300.84 ± 0.17 (n = 4)4.05 ± 1.34 (n = 4)
9) S1387Y83.13 ± 5.382.46 ± 0.96 (n = 4)2.44 ± 0.42 (n = 4)
10) S1389Y70.00 ± 7.811.26 ± 0.73 (n = 4)1.65 + 0.63 (n = 3)
11) A1458T94.33 ± 10.480.52 ± 0.21 (n = 3)1.06 ± 0.37 (n = 3)
12) Q1459H91.00 ± 2.310.69 ± 0.39 (n = 3)1.32 ± 0.29 (n = 3)
13) E1517K72.88 ± 5.851.73 ± 0.39 (n = 3)1.96 ± 0.55 (n = 4)
Mean of dominant diazoxide-unresponsive SUR1 mutations84.6 ± 4.64 (n = 13)1.42 ± 0.35 (n = 13)*1.83 ± 0.18 (n = 13)
Mean of dominant diazoxide-responsive SUR1 mutations93.68 ± 5.07 (n = 10)14.52 ± 5.15 (n = 10)18.33 ± 6.06 (n = 10)
Wild type10061.19 ± 5.53 (n = 11)77.8 ± 2.2 (n = 9)
  • Data are means ± SE.

  • *Compared with the dominant diazoxide-responsive group, P = 0.0003.

  • †Compared with the dominant diazoxide-responsive group, P = 0.0002.