A dynamic approach reveals non-muscle myosin influences the overall smooth muscle cross-bridge cycling rate.
Recent evidence suggests that non-muscle myosin IIB (NMIIB) contributes to smooth muscle contraction. This study was designed to determine the effects of NMIIB on the cross-bridge cycling rate. The cross-bridge cycling rate was investigated using sinusoidal analysis. Frequency analysis revealed two asymptotes in the Bode plot of the data; and the intersection of the asymptotes (corner frequency) was higher for the B(+/-) strain (8.73+/-1.10 Hz vs 16.56+/-1.26 Hz, P<0.05), consistent with a higher overall cross-bridge cycling rate in heterozygous NMIIB KO (B(+/-)) vs WT mice. These results demonstrate that because of their long duty cycle, NMIIB cross-bridges act as an internal load on smooth muscle myosin to decrease the overall cross-bridge cycling rate and muscle V(max) during force maintenance.
Guvenc
Bilge
B
Department of Biomedical Engineering and Physiology, Mayo Medical School, Rochester, MN, USA.
Ustunel
Cansel
C
Ozturk
Necla
N
Brozovich
Frank V
FV
D000818:Animals; D015153:Blotting, Western; D066298:In Vitro Techniques; D051379:Mice; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000378:metabolism* / Q000502:physiology*; D009218:Myosins / Q000378:metabolism*; D013696:Temperature
D009218:Myosins