Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig.
Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig.
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DOI：
10.1152/ajpcell.00269.2009
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发表时间：
2010-02
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通讯作者：
Masaru Watanabe;Masatoshi Yumoto;Hideyuki Tanaka;Hong Hui Wang;Takeshi Katayama;S. Yoshiyama;J. Black;S. Thatcher;K. Kohama
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文献类型：
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作者：
Masaru Watanabe;Masatoshi Yumoto;Hideyuki Tanaka;Hong Hui Wang;Takeshi Katayama;S. Yoshiyama;J. Black;S. Thatcher;K. Kohama
为了探讨blebbistatin，肌球蛋白II的有效抑制剂，对平滑肌收缩的抑制作用的确切机制，我们研究了blebbistatin对豚鼠盲肠带皮（细胞膜透化）制剂的机械性能和收缩丝结构的影响。在任何给定的Ca（2+）浓度下，10 μ M或更高浓度的Blebbistatin抑制Ca（2+）诱导的张力发展，但对Ca（2+）诱导的肌球蛋白轻链磷酸化几乎没有影响。Blebbistatin也抑制了10和2.75 mM Mg（2+）诱导的，“肌球蛋白轻链磷酸化独立”的张力发展超过10 μ M。此外，blebbistatin诱导平滑肌肌球蛋白（SMM）的构象变化，并破坏SMM和细丝的排列，导致肌动蛋白-SMM相互作用的抑制，而与Ca（2+）激活无关。此外，blebbistatin在10 μ M左右部分抑制豚鼠盲肠带肌球蛋白的Mg（2+）-ATP酶活性。这些结果表明，blebbistatin抑制皮肤平滑肌收缩通过破坏结构的SMM由代理。
To explore the precise mechanisms of the inhibitory effects of blebbistatin, a potent inhibitor of myosin II, on smooth muscle contraction, we studied the blebbistatin effects on the mechanical properties and the structure of contractile filaments of skinned (cell membrane permeabilized) preparations from guinea pig taenia cecum. Blebbistatin at 10 microM or higher suppressed Ca(2+)-induced tension development at any given Ca(2+) concentration but had little effects on the Ca(2+)-induced myosin light chain phosphorylation. Blebbistatin also suppressed the 10 and 2.75 mM Mg(2+)-induced, "myosin light chain phosphorylation-independent" tension development at more than 10 microM. Furthermore, blebbistatin induced conformational change of smooth muscle myosin (SMM) and disrupted arrangement of SMM and thin filaments, resulting in inhibition of actin-SMM interaction irrespective of activation with Ca(2+). In addition, blebbistatin partially inhibited Mg(2+)-ATPase activity of native actomyosin from guinea pig taenia cecum at around 10 microM. These results suggested that blebbistatin suppressed skinned smooth muscle contraction through disruption of structure of SMM by the agent.