Table I. The effect of phosphorylation on the interaction between MBD-ank and the ankyrin-binding motif of sodium channels.
| Immobilized construct | MBD | CK2 phosphorylation | kon | koff | KD |
|---|---|---|---|---|---|
| M−1s−1 | s−1 | M | |||
| GST-Nav1.2 1,080–1,203 | ankG | − | NA | NA | 1.7 ± 0.5 × 10−6a |
| ankB | − | NA | NA | 1.2 ± 0.4 × 10−6a | |
| ankG | + | 42.4 ± 41.6 × 105 | 2.1 ± 0.8 × 10−3 | 0.9 ± 0.7 × 10−9 | |
| ankB | + | 28.0 ± 11.0 × 105 | 3.0 ± 0.1 × 10−3 | 1.2 ± 0.4 × 10−9 | |
| GST-Nav1.2 989–1,133 | ankB | − | NA | NA | 1.3 ± 0.2 × 10−6a |
| + | 60.1 ± 39.8 × 105 | 2.3 ± 0.1 × 10−3 | 0.5 ± 0.2 × 10−9 | ||
| GST-Nav1.2 1,080–1,203 E1111A | ankB | − | ND | ND | ND |
| + | 1.4 ± 0.3 × 105 | 3.2 ± 0.6 × 10−3 | 2.4 ± 0.8 × 10−8 |
Mean values ± SD were obtained from three to six experiments. ankB and ankG, ankyrin B and G, respectively; NA, not applicable; ND, no binding detected.
a
KD values were calculated using steady-state analysis (see Materials and methods).