Functional Differences between the N-Terminal Domains of Mouse and Human Myosin Binding Protein-C
Figure 3
Effects of mouse and human C0, P/A, and C1 domains on motility of regulated thin filaments (F-actin + Tm + Tn) at pCa 9. (a) Compared to control experiments in the absence of added protein ( = 12), 1 M hC0C1 significantly activated filament sliding speed motility and the fraction of filaments moving ( = 8), whereas 1 M mC0C1 did not affect motility ( = 9). (b) Substitution of the human for mouse P/A domain in the mouse C0C1 backbone (mhmC0C1) activated motility ( = 7), whereas substitution of the mouse P/A domain into the human backbone (hmhC0C1) depressed motility relative to hC0C1 ( = 5). (c) Exchange of mouse and human C1 domains. The human C1 domain (mmhC0C1) activated motility (compared to mC0C1, = 5), whereas the mouse C1 domain (hhmC0C1) depressed motility (compared to hC0C1, = 6). (d) Exchange of mouse and human C0 domains. The human C0 (hmmC0C1, = 5) and mouse C0 (mhhC0C1, = 10) domains did not affect thin filament motility (compared to mC0C1 and hC0C1 controls, resp.). Data are mean ± SD. Asterisks (*) and crosses (†) denote significant differences compared to mC0C1 and hC0C1, respectively, ().
