Signaling pathways in thrombin-induced actin reorganization in pulmonary artery endothelial cells.
Signaling pathways in thrombin-induced actin reorganization in pulmonary artery endothelial cells.
复制标题
肺动脉内皮细胞中凝血酶诱导的肌动蛋白重组的信号通路。
DOI：
10.1080/019021499270402
复制
发表时间：
1999
影响因子：
1.7
通讯作者：
Davis,HW
中科院分区：
文献类型：
--
作者：
Zhao,Y;Davis,HW
内皮细胞的肌动蛋白骨架在调节细胞功能中起着重要作用。凝血酶和phorbol 12-肉豆蔻酸13-醋酸酯（PMA）（一种蛋白激酶C的激活剂；PKC）都会引起肌动蛋白的重排和内皮单层通透性的增加。相反，凝血酶，而不是PMA，诱导肌球蛋白轻链（MLC）的磷酸化，这一过程被认为是细胞收缩所必需的。因此，我们决定研究哪些信号通路参与了凝血酶诱导的肺动脉内皮细胞肌动蛋白重组。凝血酶诱导细胞骨架肌动蛋白快速和短暂的增加，与MLC磷酸化平行。+ ca2结合蛋白钙调蛋白（CaM）的拮抗或CaM依赖的MLC激酶（MLCK）的抑制可消除细胞骨架肌动蛋白的升高，而PKC的抑制则没有。相比之下，PMA+降低了细胞骨架相关的肌动蛋白，但不影响MLC的磷酸化。Ca2+离子载体A23187或内质Ca2+- atp酶抑制剂thapsigargin，无论存在或不存在PMA，都不会增加细胞骨架肌动蛋白。因此，即使PKC同时激活，细胞内Ca2+的增加也不足以将肌动蛋白重新分配到细胞骨架，这表明凝血酶募集了另一条信号通路。凝血酶和PMA都引起丝状肌动蛋白的广泛重排，导致密集的外周带消失，应力纤维增加，但每种药物都诱导了不同的形态。凝血酶诱导的肌动蛋白丝重排被PKC或MLCK抑制剂减弱。这些数据表明，PKC-和mlck依赖性通路都参与了凝血酶诱导的内皮细胞肌动蛋白重排，但肌动蛋白向细胞骨架的募集并不是这种重排所必需的。肌动蛋白和肌球蛋白募集到细胞骨架不需要PKC，但确实涉及MLCK催化的MLC磷酸化。
The actin-based cytoskeleton of endothelial cells plays an important role in regulating cell function. Both thrombin and phorbol 12-myristate 13-acetate (PMA) (an activator of protein kinase C; PKC) cause rearrangement of actin and increased permeability of endothelial monolayers. Conversely, thrombin, but not PMA, induces phosphorylation of myosin light chains (MLC), a process considered essential for cellular contraction. We, therefore, decided to investigate which signaling pathways are involved in thrombin-induced actin reorganization in pulmonary artery endothelial cells. Thrombin induced a rapid and transient increase in cytoskeletal actin that paralleled MLC phosphorylation. Antagonism of the +Ca2-binding protein, calmodulin (CaM), or inhibition of the CaM-dependent MLC kinase (MLCK) abolished the elevation in cytoskeletal actin whereas inhibition of PKC did not. In contrast, PMA+ decreased cytoskeleton-associated actin without affecting phosphorylation of MLC. A23187, a Ca2-+ ionophore, or thapsigargin, an inhibitor of endoplasmic Ca2+-ATPase, either in the presence or absence of PMA, did not increase cytoskeletal actin. Therefore, increased intracellular Ca2+, even with concurrent activation of PKC, is insufficient for redistribution of actin to the cytoskeleton, indicating that thrombin recruits yet another signaling pathway. Both thrombin and PMA caused extensive rearrangement of filamentous actin with a disappearance of the dense peripheral band and an increase in stress fibers, but each agent induced a distinct morphology. Thrombin-induced rearrangement of actin filaments was attenuated by inhibitors of either PKC or MLCK. These data suggest that both PKC- and MLCK-dependent pathways are involved in thrombin-induced endothelial cell actin rearrangement, but that recruitment of actin to the cytoskeleton is not necessary for this rearrangement. Recruitment of actin and myosin to the cytoskeleton does not require PKC but does involve MLCK- catalyzed phosphorylation of MLC.