Novel role of protein kinase C-δ Tyr311 phosphorylation in vascular smooth muscle cell hypertrophy by angiotensin II
Novel role of protein kinase C-δ Tyr311 phosphorylation in vascular smooth muscle cell hypertrophy by angiotensin II
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DOI：
10.1161/hypertensionaha.107.101253
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发表时间：
2008-02-01
期刊：
影响因子：
8.3
通讯作者：
Eguchi, Satoru
中科院分区：
文献类型：
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作者：
Nakashima, Hidekatsu;Frank, Gerald D.;Eguchi, Satoru
我们之前已经证明，激活蛋白激酶c - δ (PKC δ)是血管紧张素II （Ang II）诱导的血管平滑肌细胞（VSMCs）迁移所必需的。在这里，我们假设PKC在Tyr（311）的三角洲磷酸化在Ang II诱导的VSMC肥大中起关键作用。免疫印迹法用于监测PKC在Tyr位点的δ磷酸化（311），细胞大小和蛋白测量用于检测VSMCs的肥大。PKC δ在Tyr（311）位点被Ang II迅速磷酸化（0.5 ~ 10.0分钟）。这种磷酸化被Src家族激酶抑制剂和显性阴性Src明显阻断，但不被表皮生长因子受体激酶抑制剂阻断。与表达对照载体的VSMCs相比，Ang ii诱导的Akt磷酸化和增生性反应在表达PKC delta野生型的VSMCs中显著增强，而在表达PKC delta Y311F突变体的VSMCs中则明显减弱。此外，与表达对照载体的VSMCs相比，表达激酶失活PKC δ K376A的VSMCs的这些反应明显受到抑制。根据这些数据，我们得出结论，不仅PKC δ激酶激活，src依赖的Tyr（311）磷酸化也参与了Ang II诱导的Akt激活和随后的VSMC肥大，从而表明Ang II诱导的心血管疾病增强的一种新的分子机制。
We have shown previously that activation of protein kinase C-delta ( PKC delta) is required for angiotensin II (Ang II) - induced migration of vascular smooth muscle cells ( VSMCs). Here, we have hypothesized that PKC delta phosphorylation at Tyr(311) plays a critical role in VSMC hypertrophy induced by Ang II. Immunoblotting was used to monitor PKC delta phosphorylation at Tyr(311), and cell size and protein measurements were used to detect hypertrophy in VSMCs. PKC delta was rapidly ( 0.5 to 10.0 minutes) phosphorylated at Tyr(311) by Ang II. This phosphorylation was markedly blocked by an Src family kinase inhibitor and dominant-negative Src but not by an epidermal growth factor receptor kinase inhibitor. Ang II-induced Akt phosphorylation and hypertrophic responses were significantly enhanced in VSMCs expressing PKC delta wild-type compared with VSMCs expressing control vector, whereas the enhancements were markedly diminished in VSMCs expressing a PKC delta Y311F mutant. Also, these responses were significantly inhibited in VSMCs expressing kinase-inactive PKC delta K376A compared with VSMCs expressing control vector. From these data, we conclude that not only PKC delta kinase activation but also the Src-dependent Tyr(311) phosphorylation contributes to Akt activation and subsequent VSMC hypertrophy induced by Ang II, thus signifying a novel molecular mechanism for enhancement of cardiovascular diseases induced by Ang II.