MYOSIN LIGHT CHAIN PHOSPHORYLATION ASSOCIATED WITH CONTRACTION IN ARTERIAL SMOOTH-MUSCLE
MYOSIN LIGHT CHAIN PHOSPHORYLATION ASSOCIATED WITH CONTRACTION IN ARTERIAL SMOOTH-MUSCLE
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DOI：
10.1152/ajpcell.1981.240.5.c222
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发表时间：
1981-01-01
影响因子：
--
通讯作者：
MURPHY, RA
中科院分区：
文献类型：
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作者：
DRISKA, SP;AKSOY, MO;MURPHY, RA
Ca2+ 通过激活内源性肌球蛋白轻链激酶 (MLCK) 来启动平滑肌收缩，该激酶使肌球蛋白的 20,000 道尔顿轻链 (LC 20) 磷酸化，这一假设在猪颈动脉中层制备的组织中进行了测试。未受刺激的低色调组织表现出低水平的磷酸化 LC 20。用含有 1.6 mM CaCl2 的高 K+ 生理盐溶液刺激后，LC 20 磷酸化在 30 秒内增加至 0.6 mol P/mol LC 20。这种增加先于力量发展，需要 2-4 分钟才能达到最大稳态值 3.34 .+-。 0.15（SE）× 105 牛/平方米。该假设得到支持，因为刺激对于准备来说是次最大的。 LC 20 磷酸化从达到稳态力之前的峰值显着下降，刺激 10 分钟后达到接近对照水平。 Ca2+刺激的LC 20 磷酸化显然是一种重要的生理控制机制；维持等长收缩力还涉及其他因素。
The hypothesis that Ca2+ initiates contraction in smooth muscle by activating an endogenous myosin light chain kinase (MLCK) that phosphorylates the 20,000 dalton light chain (LC 20) of myosin was tested in tissues prepared from the media of swine carotid arteries. Unstimulated tissues with low levels of tone exhibited low levels of phosphorylated LC 20. On stimulation with a high-K+ physiological salt solution containing 1.6 mM CaCl2, LC 20 phosphorylation increased to 0.6 mol P/mol LC 20 within 30 s. This increase preceded force development, which required 2-4 min to attain a maximum steady-state value of 3.34 .+-. 0.15 (SE) .times. 105 N/m2. The hypothesis was supported as the stimulus was submaximal for the preparation. LC 20 phosphorylation declined significantly from its peak value before steady-state force was attained, reaching near control levels after 10 min of stimulation. Ca2+-stimulated LC 20 phosphorylation apparently is an important physiological control mechanism; additional factors are involved in the maintenance of tonic isometric force.