Table 3.
Maximal ATPase activity and in vitro motility of WT and mutant MYH11 constructs
| Construct | PHOS | Maximal actin-activated ATPase,* sec−1 per head ± SD† | In vitro motility,‡ μm/sec ± SD† |
|---|---|---|---|
| MYH11-HMM WT | −PHOS | ≈0 | 0 (no observed motility) |
| + PHOS | 0.87 ± 0.06† | 0.36 ± 0.09† | |
| MYH11-HMM R501L | −PHOS | 0.43 ± 0.02 | 0.12 ± 0.03 |
| + PHOS | 0.41 ± 0.03 | 0.13 ± 0.04 | |
| MYH11-HMM K1044N | −PHOS | 0.48 ± 0.03 | 0.14 ± 0.04 |
| + PHOS | 0.49 ± 0.04 | 0.16 ± 0.04 | |
| MYH11− full-length WT | − PHOS | ND | 0 (no observed motility) |
| + PHOS | ND | 0.35 ± 0.11† | |
| MYH11− full-length with C9 mutation | −PHOS | ND | 0.17 ± 0.06 |
| +PHOS | ND | 0.13 ± 0.04 | |
| MYH11− full-length with C7 mutation | −PHOS | ND | 0.26 ± 0.05 |
| +PHOS | ND | 0.35 ± 0.09 |
ND, not determined. PHOS, phosphorylation status.
*Data pooled from triplicate assays on three independent protein preparations.
†Significant difference (P < 0.01) between unphosphorylated and phosphorylated myosin, demonstrating the presence of regulation. P values were calculated using Student's t test, comparing the unphosphorylated and the phosphorylated data groups for each mutant.
‡Data pooled from three independentprotein preparations.