Actin depolymerization via the β-adrenoceptor in airway smooth muscle cells:: a novel PKA-independent pathway
Actin depolymerization via the β-adrenoceptor in airway smooth muscle cells:: a novel PKA-independent pathway
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DOI：
10.1152/ajpcell.2001.281.5.c1468
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发表时间：
2001-11-01
影响因子：
5.5
通讯作者：
Emala, CW
中科院分区：
文献类型：
--
作者：
Hirshman, CA;Zhu, DF;Emala, CW
肌动蛋白是一种主要的功能和结构上的细胞骨架蛋白，参与细胞运动、胞质分裂、收缩以及细胞形状和极性的控制等多种过程。虽然已知许多细胞外信号介导肌动蛋白细丝聚合，但对介导肌动蛋白细胞骨架解聚的信号知之甚少。人气道平滑肌细胞短暂暴露于异丙肾上腺素、Forsklin或cAMP依赖的蛋白激酶A(PKA)激动剂刺激性非对映异构体3‘，5’-环磷酸腺苷(Sp-cAMP)。肌动蛋白聚合通过同时染色丝状肌动蛋白与FITC-鬼臼蛋白和球状肌动蛋白与德州红DNase I，异丙肾上腺素、Forsklin或Sp-cAMPS诱导肌动蛋白解聚，以丝状/球状荧光染色强度降低表示。3‘，5’-环硫代磷酸腺苷的PKA抑制剂RP非对映异构体(RP-cAMP)可完全抑制Forsklin诱导的解聚，但仅部分抑制异丙肾上腺素诱导的解聚。蛋白酪氨酸激酶抑制剂Genistein或Tyrphostin A23也部分抑制了异丙肾上腺素诱导的肌动蛋白解聚。相反，RP-cAMP和任何一种酪氨酸激酶抑制剂的组合在抑制异丙肾上腺素诱导的肌动蛋白解聚方面具有相加的作用。这些结果表明，PKA依赖的和非依赖的通路都介导了人气道平滑肌细胞中肌动蛋白的解聚。
Actin is a major functional and structural cytoskeletal protein that mediates such diverse processes as motility, cytokinesis, contraction, and control of cell shape and polarity. While many extracellular signals are known to mediate actin filament polymerization, considerably less is known about signals that mediate depolymerization of the actin cytoskeleton. Human airway smooth muscle cells were briefly exposed to isoproterenol, forskolin, or the cAMP-dependent protein kinase A (PKA) agonist stimulatory diastereoisomer of adenosine 3', 5'-cyclic monophosphate (Sp-cAMPS). Actin polymerization was measured by concomitant staining of filamentous actin with FITC-phalloidin and globular actin with Texas red DNase I. Isoproterenol, forskolin, or Sp-cAMPS induced actin depolymerization, indicated by a decrease in the intensity of filamentous/globular fluorescent staining. The PKA inhibitor Rp diastereomer of adenosine 3', 5'-cyclic monophosphothioate (Rp-cAMPS) completely inhibited forskolin-stimulated depolymerization, whereas it only partially inhibited isoproterenol-induced depolymerization. The protein tyrosine kinase inhibitors genistein or tyrphostin A23 also partially inhibited isoproterenol-induced actin depolymerization. In contrast, the combination of Rp-cAMPS and either tyrosine kinase inhibitor had an additive effect at inhibiting isoproterenol-induced actin depolymerization. These results suggest that both PKA-dependent and -independent pathways mediate actin depolymerization in human airway smooth muscle cells.