Involvement of PYK2 in angiotensin II signaling of vascular smooth muscle cells
Involvement of PYK2 in angiotensin II signaling of vascular smooth muscle cells
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DOI：
10.1161/01.hyp.33.1.201
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发表时间：
1999-01-01
期刊：
影响因子：
8.3
通讯作者：
Hirata, Y
中科院分区：
文献类型：
--
作者：
Eguchi, S;Iwasaki, H;Hirata, Y
PYK2是一种最近发现的Ca2+敏感酪氨酸激酶，通过几种G蛋白偶联受体参与细胞外信号调节激酶（ERK）的激活。我们已经报道了血管紧张素II （Ang II）诱导Ca2+依赖性的表皮生长因子受体（EGFR）的反激活，EGFR作为预激活的c-Src和下游适配器（Shc/Grb2）的支架，导致培养大鼠血管平滑肌细胞（VSMC）中的ERK激活。在这里，我们证明了PYK2参与了这个级联。Ang II快速诱导PYK2的酪氨酸磷酸化，其作用被AT(1)受体拮抗剂和细胞内Ca2+螯合剂完全抑制，Ca2+离子载体也诱导PYK2的酪氨酸磷酸化水平与Ang II相当，而磷酯诱导的磷酸化水平低于Ang II。此外，在Ang II刺激后，PYK2与催化活性的c-Src形成复合物共可沉淀。尽管选择性EGFR激酶抑制剂完全消除了Ang ii诱导的Grb2对EGFR的募集，并显着减弱了Ang ii诱导的ERK活化，但它对Ang ii诱导的PYK2酪氨酸磷酸化或其与c-Src和Grb2的关联没有影响。这些数据表明AT(1)受体使用Ca2+依赖性PYK2激活c-Src，从而导致EGFR反激活，在大鼠VSMC中主要招募Grb2。
PYK2, a recently identified Ca2+-sensitive tyrosine kinase, has been implicated in extracellular signal-regulated kinase (ERK) activation via several G protein-coupled receptors. We have reported that angiotensin II (Ang II) induces Ca2+-dependent transactivation of the epidermal growth factor receptor (EGFR) which serves as a scaffold for preactivated c-Src and downstream adaptors (Shc/Grb2), leading to ERK activation in cultured rat vascular smooth muscle cells (VSMC). Herein we demonstrate the involvement of PYK2 in this cascade. Ang II rapidly induced tyrosine phosphorylation of PYK2, whose effect was completely inhibited by an AT(1) receptor antagonist and an intracellular Ca2+ chelator, A Ca2+ ionophore also induced PYK2 tyrosine phosphorylation to a level comparable with that by Ang II, whereas phorbol ester-induced phosphorylation was less than that by Ang II. Moreover, PYK2 formed a complex coprecipitable with catalytically active c-Src after Ang II stimulation. Although a selective EGFR kinase inhibitor completely abolished Ang II-induced recruitment of Grb2 to EGFR and markedly attenuated Ang II-induced ERK activation, it had no effect on Ang II-induced PYK2 tyrosine phosphorylation or its association with c-Src and Grb2. These data suggest that the AT(1) receptor uses Ca2+-dependent PYK2 to activate c-Src, thereby leading to EGFR transactivation, which preponderantly recruits Grb2 in rat VSMC.