Wong J Z, Woodcock-Mitchell J, Mitchell J, Rippetoe P, White S, Absher M, Baldor L, Evans J, McHugh K M, Low R B
Department of Molecular Physiology, University of Vermont, Burlington 05405, USA.
Am J Physiol. 1998 May;274(5):L786-92. doi: 10.1152/ajplung.1998.274.5.L786.
In this study, the expression of smooth muscle actin and myosin was examined in cultures of rat tracheal smooth muscle cells. Protein and mRNA analyses demonstrated that these cells express alpha- and gamma-smooth muscle actin and smooth muscle myosin and nonmuscle myosin-B heavy chains. The expression of the smooth muscle specific actin and myosin isoforms was regulated in the same direction when growth conditions were changed. Thus, at confluency in 1 or 10% serum-containing medium as well as for low-density cells (50-60% confluent) deprived of serum, the expression of the smooth muscle forms of actin and myosin was relatively high. Conversely, in rapidly proliferating cultures at low density in 10% serum, smooth muscle contractile protein expression was low. The expression of nonmuscle myosin-B mRNA and protein was more stable and was upregulated only to a small degree in growing cells. Our results provide new insight into the molecular basis of differentiation and contractile function in airway smooth muscle cells.
在本研究中，检测了大鼠气管平滑肌细胞培养物中平滑肌肌动蛋白和肌球蛋白的表达。蛋白质和mRNA分析表明，这些细胞表达α-和γ-平滑肌肌动蛋白、平滑肌肌球蛋白以及非肌肉肌球蛋白-B重链。当生长条件改变时，平滑肌特异性肌动蛋白和肌球蛋白同工型的表达在相同方向上受到调节。因此，在含1%或10%血清的培养基中达到汇合状态时，以及对于缺乏血清的低密度细胞（50-60%汇合），肌动蛋白和平滑肌形式的肌球蛋白的表达相对较高。相反，在含10%血清的低密度快速增殖培养物中，平滑肌收缩蛋白的表达较低。非肌肉肌球蛋白-B mRNA和蛋白质的表达更稳定，并且在生长细胞中仅上调至小程度。我们的结果为气道平滑肌细胞分化和收缩功能的分子基础提供了新的见解。
