鸡胚成纤维细胞中不依赖钙离子的肌球蛋白II磷酸化与收缩

Ca2+-independent myosin II phosphorylation and contraction in chicken embryo fibroblasts.

Kolodney M S, Thimgan M S, Honda H M, Tsai G, Yee H F

Division of Dermatology, Department of Medicine, 1519 MacDonald Research Laboratory, UCLA School of Medicine, Los Angeles, CA 90095, USA.

J Physiol. 1999 Feb 15;515 ( Pt 1)(Pt 1):87-92. doi: 10.1111/j.1469-7793.1999.087ad.x.

Non-muscle contraction is widely believed to be mediated through Ca2+-stimulated myosin II regulatory light chain (LC20) phosphorylation, similar to the contractile regulation of smooth muscle. However, this hypothesis lacks conclusive experimental support. 2. By modulating chicken embryo fibroblast cytosolic Ca2+ concentration ([Ca2+]i), we investigated the putative role of [Ca2+]i in fetal bovine serum (FBS)-stimulated LC20 phosphorylation and force development in these cells. 3. Eliminating the FBS-stimulated rise in [Ca2+]i with the Ca2+ chelator BAPTA only partially inhibited FBS-stimulated LC20 phosphorylation and did not significantly alter the magnitude of FBS-stimulated isometric contraction. 4. Ionomycin (1 microM) produced a larger but shorter lasting rise in [Ca2+]i relative to FBS. However, ionomycin only stimulated a small and transient increase in LC20 phosphorylation and did not cause contraction. 5. We conclude that fibroblasts differ from smooth muscle in that LC20 phosphorylation and contraction are predominantly regulated independently of [Ca2+]i.

人们普遍认为，非肌肉收缩是通过钙刺激的肌球蛋白II调节轻链（LC20）磷酸化介导的，这与平滑肌的收缩调节类似。然而，这一假设缺乏确凿的实验支持。2. 通过调节鸡胚成纤维细胞胞质钙浓度（[Ca2+]i），我们研究了[Ca2+]i在胎牛血清（FBS）刺激的这些细胞中LC20磷酸化和力产生中的假定作用。3. 用钙螯合剂BAPTA消除FBS刺激的[Ca2+]i升高，仅部分抑制了FBS刺激的LC20磷酸化，且未显著改变FBS刺激的等长收缩幅度。4. 离子霉素（1 microM）相对于FBS使[Ca2+]i产生更大但持续时间更短的升高。然而，离子霉素仅刺激LC20磷酸化出现小的短暂增加，并未引起收缩。5. 我们得出结论，成纤维细胞与平滑肌不同，因为LC20磷酸化和收缩主要独立于[Ca2+]i进行调节。

Ca2+-independent myosin II phosphorylation and contraction in chicken embryo fibroblasts.