HSP27 phosphorylation and interaction with actin-myosin in smooth muscle contraction
HSP27 phosphorylation and interaction with actin-myosin in smooth muscle contraction
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DOI：
10.1152/ajpgi.00141.2001
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发表时间：
2002-05-01
影响因子：
4.5
通讯作者：
Bitar, KN
中科院分区：
文献类型：
--
作者：
Bitar, KN
我们研究了热休克蛋白27(HSP27)的磷酸化作用以及HSP27与收缩蛋白肌动蛋白、肌球蛋白和原肌球蛋白的关系。[P-32]正磷酸盐标记血管内皮细胞。蛋白激酶C(PKC)的激活剂C2-神经酰胺(0.1um)诱导HSP27的磷酸化持续增加，该作用可被calphostin C抑制。C2-神经酰胺(0.1um)诱导的结肠平滑肌细胞持续收缩伴随着HSP27与原肌球蛋白结合和HSP27与肌动蛋白结合的显著增加。S刺激后30min开始显著升高，并持续至4min。在免疫荧光标记原肌球蛋白、肌动蛋白和HSP27后，共聚焦显微镜观察到，收缩也与HSP27与原肌球蛋白和肌动蛋白的强烈共存有关。将HSP27磷酸化突变体导入平滑肌细胞，结果表明，HSP27的磷酸化可影响肌球蛋白与肌动蛋白的结合。综上所述，1)HSP27的磷酸化似乎是HSP27在细胞内重组所必需的，并且似乎与PKC信号转导途径直接相关；2)激动剂诱导的HSP27的磷酸化通过原肌球蛋白的细丝调节来调节肌动蛋白-肌球蛋白的相互作用。
We have investigated the role of heat shock protein 27 (HSP27) phosphorylation and the association of HSP27 with contractile proteins actin, myosin, and tropomyosin. Smooth muscle cells were labeled with [P-32] orthophosphate. C2-ceramide (0.1 muM), an activator of protein kinase C (PKC), induced a sustained increase in HSP27 phosphorylation that was inhibited by calphostin C. C2-ceramide-induced (0.1 muM) sustained colonic smooth muscle cell contraction was accompanied by significant increases in the association of HSP27 with tropomyosin and in the association of HSP27 with actin. The significant increases occurred at 30 s after stimulation and were sustained at 4 min. Contraction was also associated with strong colocalization of HSP27 with tropomyosin and with actin as observed after immunofluorescent labeling of tropomyosin, actin, and HSP27 followed by confocal microscopy. Transfection of smooth muscle cells with HSP27 phosphorylation mutants indicated that phosphorylation of HSP27 could affect myosin association with actin. In conclusion 1) HSP27 phosphorylation appears to be necessary for reorganization of HSP27 inside the cell and seems to be directly correlated with the PKC signal transduction pathway, and 2) agonist-induced phosphorylation of HSP27 modulates actin-myosin interaction through thin-filament regulation of tropomyosin.