Regulation of catch muscle by twitchin phosphorylation: Effects on force, ATPase, and shortening
Regulation of catch muscle by twitchin phosphorylation: Effects on force, ATPase, and shortening
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DOI：
10.1016/s0006-3495(98)77631-3
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发表时间：
1998-10-01
影响因子：
3.4
通讯作者：
Siegman, MJ
中科院分区：
文献类型：
--
作者：
Butler, TM;Mooers, SU;Siegman, MJ
最近对紫贻贝（Mytilus edulis）的透化前足丝牵开肌（ABRM）的实验表明，在pCa > 8时，tickin的磷酸化释放抓力，并降低在基底上但次最大值[Ca 2 +]的力。Twitchin磷酸化降低了力，而ATP酶活性没有检测到变化，因此增加了在亚饱和[Ca 2 +]时维持力的能量成本。类似地，在任何[Ca 2 +]条件下，tickin磷酸化均不会导致无负荷缩短速度（Vo）发生变化，但当在相等的次最大力下进行比较时，tickin磷酸化时Vo更高。在钙激活过程中，由tickin磷酸化控制的力维持结构调节到30%Lo释放，以维持较短长度的力。数据：表明在捕捉和钙介导的次最大收缩过程中，tickin磷酸化去除了一种结构，该结构保持了与...非常低的ATP酶，但在次最大钙激活期间可以缓慢循环。本文提出了一个基于Hai和Murphy（1988）修正的定量跨桥渔获量模型。Am. J.Physiol.254：C99-C106）用于调节哺乳动物平滑肌的闩锁桥模型。
Recent experiments on permeabilized anterior byssus retractor muscle (ABRM) of Mytilus edulis have shown that phosphorylation of twitchin releases catch force at pCa > 8 and decreases force at suprabasal but submaximum [Ca2+]. Twitchin phosphorylation decreases force with no detectable change in ATPase activity, and thus increases the energy cost of force maintenance at subsaturating [Ca2+]. Similarly, twitchin phosphorylation causes no change in unloaded shortening velocity (Vo) at any [Ca2+], but when compared at equal submaximum forces there is a higher Vo when twitchin is phosphorylated. During calcium activation, the force-maintaining structure controlled by twitchin phosphorylation adjusts to a 30% Lo release to maintain force at the shorter length. The data: suggest that during both catch and calcium-mediated submaximum contractions, twitchin phosphorylation removes a structure that maintains force with.. very low ATPase, but which can slowly cycle during submaximum calcium activation. A quantitative cross-bridge model of catch is presented that is based on modifications of the Hai and Murphy (1988. Am. J. Physiol. 254:C99-C106) latch bridge model for regulation of mammalian smooth muscle.