Figure 6
From: Smooth muscle-like Ca2+-regulation of actin–myosin interaction in adult jellyfish striated muscle
Ca2+-dependent activation and phosphorylation of actomyosin. (a) Mg-ATPase activity of actomyosin in the absence and presence of Ca2+. Ca2+-dependent activation was enhanced by adding myosin light chain kinase (MLCK) and calmodulin (CaM). The values were presented as means and standard errors (n = 5). The values were also statistically compared by two-tailed t-test (n = 5), and the p-values are indicated. (b) Phos-Tag SDS-PAGE of actomyosin incubated for 10 min under the same conditions as the ATPase assay. Abbreviations: MRLC, myosin regulatory light chain; MHC-II, myosin-II heavy chain; PM, paramyosin-like protein; MELC, myosin essential light chain; Tm, tropomyosin. (c) Comparison of the mass spectra of tryptic digests of unphosphorylated (upper) and phosphorylated (lower) myosin regulatory light chain (MRLC). The mass increment of 79.94 Da corresponds to phosphorylation of a single hydroxyl group.
