TABLE 1.
Subcellular distributions of mutations at positions 330 and 502 in the eYFP-Kv1.4 channel
The data represent compilations of the relative surface versus endoplasmic reticulum distributions of the indicated Kv1.4 mutant constructs expressed in HEK293 cells as determined by electrophysiology and flow cytometry (normalize to HA-tagged WT). All data are shown as mean ± S.E. (n ≥ 5). (See also supplemental Fig. S3.) Note the correlation between channel surface expression and currents, with the exception of E502T, which shows 30% surface expression but low currents, and T330K, which shows partial surface expression and modest currents. ND denotes not determined.
|
Mutant
|
Potential
bridgea
|
Surface
%b
|
Current densities (PA/PE)
|
|
|---|---|---|---|---|
| Peak | Steady state | |||
| Thr-330 (WT) | Thr ↔ Glu (WT) | 100 | 1279 ± 144 (7) | 748 ± 104 (7) |
| T330S | Ser ↔ Glu | 65 ± 11 | 1418 ± 124 (7) | 828 ± 79 (7) |
| T330K | Lys ↔ Glu | 21 ± 3 | 226 ± 67 (8) | 223 ± 67 (8) |
| T330A | Ala ↔ Glu | 9 ± 5 | 45 ± 11 (5) | 33 ± 9 (5) |
| E502V | Thr ↔ Val | 7 ± 7 | 28 ± 6 (4) | 21 ± 5 (4) |
| E502D | Thr ↔ Asp | 30 ± 4 | ND | ND |
| E502T | Thr ↔ Thr | 28 ± 10 | 27 ± 5 (4) | 20 ± 5 (4) |
| E502K | Thr ↔ Lys | 9 ± 5 | 54 ± 6 (5) | 37 ± 4 (5) |
| T330S,E502D | Ser ↔ Asp | 12 ± 3 | ND | ND |
| T330E,E502T | Glu ↔ Thr | 9 ± 5 | 35 ± 6 (6) | 25 ± 4 (6) |
| T330K,E502K | Lys ↔ Lys | 0 ± 0 | 40 ± 20 (5) | 30 ± 16 (5) |
a
Between positions 330 and 502.
b
FACS analysis (n > 5).