Conventional protein kinase C mediates phorbol-dibutyrate-induced cytoskeletal remodeling in A7r5 smooth muscle cells
Conventional protein kinase C mediates phorbol-dibutyrate-induced cytoskeletal remodeling in A7r5 smooth muscle cells
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DOI：
10.1006/excr.2002.5592
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发表时间：
2002-10-15
影响因子：
3.7
通讯作者：
Gimona, M
中科院分区：
文献类型：
--
作者：
Hai, CM;Hahne, P;Gimona, M
佛波酯(PDBu)可诱导A7r5细胞足体样结构的形成和肌动蛋白应激纤维的部分解体。这些足体含有α-肌动蛋白、F-肌动蛋白和纽蛋白，并呈现出管状、柱状结构，垂直于PDBu处理的细胞底部。传统的蛋白激酶C(PKC)拮抗剂GO6976在0.1um时可抑制PDBu诱导的细胞骨架重构，而新型PKC拮抗剂rotlerin在10um时无效。PDBu诱导A7r5细胞中传统的PKC-α而不是新的PKC-Delta移位到足体形成部位。虽然在Y-27632和PDBu处理的细胞中都观察到肌动蛋白应激纤维的部分解体，但只有Y-27632处理的细胞在局灶性粘连的数量和大小上显著减少。此外，PDBu还恢复了Y-27632处理的细胞的灶性粘连。α-Actinin GFP的实时视频荧光显微镜显示，在PDBu治疗期间，在足体的快速形成和动态重组之前，有大约20分钟的滞后期。这些发现表明，传统的PKCs介导了PDBu诱导的A7r5细胞中动态足体样结构的形成，而Rho-Kinase不太可能是其潜在的机制。足体柱可以代表分子支架，PKC-α在其中磷酸化调节蛋白，这是平滑肌细胞中钙敏化所必需的。(C)2002年埃尔塞维尔科学公司(美国)。
Phorbol dibutyrate (PDBu) induced the formation of podosome-like structures together with partial disassembly of actin stress fibers in A7r5 smooth muscle cells. These podosomes contained alpha-actinin, F-actin, and vinculin and exhibit a tubular, column-like structure arising perpendicularly from the bottom of PDBu-treated cells. The conventional protein kinase C (PKC) antagonist, GO6976, inhibited PDBu-induced cytoskeletal remodeling at 0.1 muM, whereas the novel PKC antagonist, rottlerin, was ineffective at 10 muM. PDBu induced the translocation of the conventional PKC-alpha but not the novel PKC-delta to the sites of podosome formation in A7r5 cells. Although partial disassembly of actin stress fibers was observed in both Y-27632- and PDBu-treated cells, focal adhesions were much reduced in number and size only in Y-27632-treated cells. Furthermore, PDBu restored focal adhesions in Y-27632-treated cells. Live video fluorescence microscopy of alpha-actinin GFP revealed a lag phase of about 20 min prior to the rapid formation and dynamic reorganization of podosomes during PDBu treatment. These findings suggest that conventional PKCs mediate PDBu-induced formation of dynamic podosome-like structures in A7r5 cells, and Rho-kinase is unlikely to be the underlying mechanism. The podosome columns could represent molecular scaffolds where PKC-alpha phosphorylates regulatory proteins necessary for Ca2+ sensitization in smooth muscle cells. (C) 2002 Elsevier Science (USA).