The small heat shock-related protein, HSP20, is a cAMP-dependent protein kinase substrate that is involved in airway smooth muscle relaxation
The small heat shock-related protein, HSP20, is a cAMP-dependent protein kinase substrate that is involved in airway smooth muscle relaxation
复制标题
DOI：
10.1152/ajplung.00235.2007
复制
发表时间：
2008-01-01
影响因子：
4.9
通讯作者：
Brophy, Colleen M.
中科院分区：
文献类型：
--
作者：
Komalavilas, Padmini;Penn, Raymond B.;Brophy, Colleen M.
cAMP/cAMP依赖性PKA通路的激活导致气道平滑肌（ASM）的松弛。本研究的目的是研究小热休克相关蛋白HSP20在介导pka依赖性ASM松弛中的作用。我们对人ASM细胞进行工程改造，使其组成性地表达绿色荧光蛋白- pka抑制融合蛋白（PKIGFP）或单独表达GFP。异丙肾上腺素（ISO）或福斯克林激活camp依赖性信号通路导致GFP中HSP20磷酸化升高，但不影响PKI-GFP细胞。Forskolin在GFP而不是pkgfp细胞中处理导致中央肌动蛋白应激纤维的丢失和局灶黏附复合物的数量减少。在GFP细胞中，这种应激纤维的丢失与肌动蛋白解聚蛋白cofilin的去磷酸化有关，而与PKI-GFP细胞无关。为了证实磷酸化的HSP20在pka诱导的ASM松弛中起作用，我们用5 -羟色胺预收缩了完整的牛ASM条，然后用ISO预收缩。PKA通路的激活导致了牛ASM的松弛，这与HSP20的磷酸化和cofilin的去磷酸化有关。最后，用具有蛋白质转导结构域的HSP20的磷酸化肽模拟物处理部分放松预收缩的牛ASM条。综上所述，iso诱导的HSP20磷酸化或合成的HSP20的磷酸化肽类似物降低了肌动蛋白中cofilin的磷酸化并破坏了肌动蛋白，这表明HSP20介导肌动蛋白弛缓的一个可能机制是通过调节肌动蛋白丝动力学。
Activation of the cAMP/cAMP-dependent PKA pathway leads to relaxation of airway smooth muscle (ASM). The purpose of this study was to examine the role of the small heat shock-related protein HSP20 in mediating PKA-dependent ASM relaxation. Human ASM cells were engineered to constitutively express a green fluorescent protein-PKA inhibitory fusion protein (PKIGFP) or GFP alone. Activation of the cAMP-dependent signaling pathways by isoproterenol (ISO) or forskolin led to increases in the phosphorylation of HSP20 in GFP but not PKI-GFP cells. Forskolin treatment in GFP but not PKI-GFP cells led to a loss of central actin stress fibers and decreases in the number of focal adhesion complexes. This loss of stress fibers was associated with dephosphorylation of the actin-depolymerizing protein cofilin in GFP but not PKI-GFP cells. To confirm that phosphorylated HSP20 plays a role in PKA-induced ASM relaxation, intact strips of bovine ASM were precontracted with serotonin followed by ISO. Activation of the PKA pathway led to relaxation of bovine ASM, which was associated with phosphorylation of HSP20 and dephosphorylation of cofilin. Finally, treatment with phosphopeptide mimetics of HSP20 possessing a protein transduction domain partially relaxed precontracted bovine ASM strips. In summary, ISO-induced phosphorylation of HSP20 or synthetic phosphopeptide analogs of HSP20 decreases phosphorylation of cofilin and disrupts actin in ASM, suggesting that one possible mechanism by which HSP20 mediates ASM relaxation is via regulation of actin filament dynamics.