Word R A
Department of Obsterics and Gynecology, University of Texas Southwestern Medical Center at Dallas 75235-9032, USA.
Semin Perinatol. 1995 Feb;19(1):3-14. doi: 10.1016/s0146-0005(95)80043-3.
In summary, phosphorylation of the regulatory light chain of myosin by Ca2+/CaM-dependent MLCK plays an important role in smooth muscle contraction. Although there have been major advances in our understanding of the regulation and physiological functions of contractile proteins in smooth muscle in recent years, very little information exists on the functional status of these proteins in human myometrium during pregnancy. The simple view that contractile force in smooth muscle is proportionate to cytoplasmic Ca2+ concentrations (Ca2+i) and myosin light chain phosphorylation is now more complex as more experiments provide insights into mechanisms of regulation of the contractile elements. MLCK can be phosphorylated, which desensitizes its activation by Ca2+/CaM, and protein phosphatase activity toward myosin may also be regulated. Examples in smooth muscle tissue are sparse, and the different mechanisms by which these processes may be adapted in uterine smooth muscle during pregnancy are not well-defined. Much research is needed to define further the cellular, biochemical, and molecular basis for these physiological processes involved in the regulation of uterine smooth muscle contraction and relaxation.
总之，Ca2+/钙调蛋白依赖性肌球蛋白轻链激酶（MLCK）对肌球蛋白调节轻链的磷酸化在平滑肌收缩中起重要作用。尽管近年来我们对平滑肌中收缩蛋白的调节和生理功能的理解有了重大进展，但关于这些蛋白在孕期人子宫肌层中的功能状态的信息却非常少。随着越来越多的实验深入了解收缩元件的调节机制，认为平滑肌收缩力与细胞质Ca2+浓度（Ca2+i）及肌球蛋白轻链磷酸化成正比的简单观点现在变得更加复杂了。MLCK可被磷酸化，这使其对Ca2+/钙调蛋白的激活产生脱敏作用，并且针对肌球蛋白的蛋白磷酸酶活性也可能受到调节。平滑肌组织中的例子很少，而且这些过程在孕期子宫平滑肌中可能的不同适应机制尚未明确。需要进行大量研究以进一步确定参与子宫平滑肌收缩和舒张调节的这些生理过程的细胞、生化和分子基础。
