Trybus K M
Rosenstiel Research Center, Brandeis University, Waltham, MA 02254.
Cell Motil Cytoskeleton. 1991;18(2):81-5. doi: 10.1002/cm.970180202.
It is well established that light chain phosphorylation is required before a smooth muscle can generate force. The apparent modulation of shortening velocity by phosphorylation during sustained contractions may be accounted for by a mechanical interaction between rapidly cycling phosphorylated crossbridges and slowly or non-cycling dephosphorylated crossbridges. Latchbridges, force-producing dephosphorylated crossbridges, have been proposed to explain why force levels remain high at low levels of phosphorylation. The role of the thin-filament-associated proteins caldesmon and calponin in regulation remains enigmatic, but their inhibitory properties in solution would be consistent with a possible involvement in maintenance of a relaxed state.
众所周知，平滑肌产生力量之前需要轻链磷酸化。在持续收缩过程中，磷酸化对缩短速度的明显调节可能是由于快速循环的磷酸化横桥与缓慢或非循环的去磷酸化横桥之间的机械相互作用。有人提出了闩锁桥，即产生力量的去磷酸化横桥，以解释为什么在低磷酸化水平时力量水平仍然很高。与细肌丝相关的蛋白钙调蛋白和钙调磷酸酶在调节中的作用仍然是个谜，但它们在溶液中的抑制特性与可能参与维持松弛状态是一致的。
