Thrombin-induced phosphorylation of MARCKS does not alter its interactions with calmodulin or actin.
Thrombin-induced phosphorylation of MARCKS does not alter its interactions with calmodulin or actin.
复制标题
凝血酶诱导的 MARCKS 磷酸化不会改变其与钙调蛋白或肌动蛋白的相互作用。
DOI：
10.1016/s0898-6568(99)00065-0
复制
发表时间：
2000
影响因子：
4.8
通讯作者：
Davis,HW
中科院分区：
文献类型：
--
作者：
Neltner,BS;Zhao,Y;Sacks,DB;Davis,HW
豆蔻酰化富丙氨酸C激酶底物（MARCKS）是钙调蛋白（CaM）和肌动蛋白结合蛋白，也是蛋白激酶C（PKC）的重要底物。在体外磷酸化的MARCKS的PKC已被证明可以诱导钙调素和肌动蛋白的释放，从而导致的建议，MARCKS可以调节钙调素的可用性在激动剂诱导的信号。为了支持这一假设，我们以前证明，凝血酶诱导的MARCKS在内皮细胞（EC）的磷酸化平行激活肌球蛋白轻链激酶，钙调蛋白依赖性酶。为了进一步验证这一理论，我们用MARCKS cDNA转染了CHO细胞，这些细胞通常不表达显着水平的MARCKS。凝血酶刺激的肌球蛋白轻链磷酸化和敏感性，在MARCKS过表达细胞中的钙调素拮抗剂是相同的，在控制CHO细胞。与肌动蛋白细胞骨架在EC中的MARCKS显着增加后，治疗与PKC激活剂，PMA，但只有适度增强凝血酶治疗。同样，共定位的MARCKS与肌动蛋白增强时，EC受到挑战与PMA，但不是凝血酶。这些数据可以部分解释PKC独立磷酸化的MARCKS在凝血酶刺激。
Myristoylated alanine-rich C kinase substrate (MARCKS) is a calmodulin (CaM)- and actin-binding protein and prominent protein kinase C (PKC) substrate. In vitro phosphorylation of MARCKS by PKC has been shown to induce the release of both CaM and actin, leading to the suggestion that MARCKS may regulate CaM availability during agonist-induced signalling. In support of this hypothesis we previously demonstrated that thrombin-induced MARCKS phosphorylation in endothelial cells (EC) parallels activation of myosin light chain kinase, a CaM-dependent enzyme. To test this theory further, we transfected CHO cells, which normally do not express significant levels of MARCKS, with a MARCKS cDNA. The thrombin-stimulated phosphorylation of myosin light chains and the sensitivity to CaM antagonists in the MARCKS overexpressing cells was the same as that in control CHO cells. MARCKS associated with the actin cytoskeleton in EC was markedly increased upon treatment with the PKC activator, PMA, but only modestly enhanced by thrombin treatment. Similarly, colocalisation of MARCKS with actin was enhanced when the EC were challenged with PMA but not thrombin. These data may be partially explained by PKC-independent phosphorylation of MARCKS in response to thrombin stimulation.