Long-term regulation of Na(+)-H+ exchange in vascular smooth muscle cells: role of protein kinase C.
Long-term regulation of Na(+)-H+ exchange in vascular smooth muscle cells: role of protein kinase C.
复制标题
血管平滑肌细胞Na()-H交换的长期调节：蛋白激酶C的作用。
DOI：
10.1152/ajpcell.1991.260.3.c562
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Berk,BC
中科院分区：
文献类型：
--
作者：
Mitsuka,M;Berk,BC
细胞内pH(Phi)的调节对血管平滑肌细胞(VSMC)的收缩张力和生长起着重要作用。我们已经证明，增殖的VSMC的PHI(7.25)比生长停滞的细胞(7.10)更具碱性。为了研究Na(+)-H+交换器在VSMC Phi生长依赖性调控中的作用，测定了乙基异丙基氨氯吡咪(EIPA)敏感的Na+内流。生长受阻的VSMC暴露于10%的血清中，首先增加Na+内流(30min是基线的145%)，然后下降(24h是基线的52%)。通过对Na(+)-H+交换器外部Na+结合部位性质的分析，研究了血清对Na(+)-H+交换器动力学性质的影响。生长受阻的VSMC暴露于10%的血清中24小时，对外源Na+的Km从54 mm增加到380 mm，Vmax从155 nmolNa+·mg蛋白-1.min-1增加到199nmolNa+·mg蛋白-1.min-1。Km的变化是由于蛋白激酶C(PKC)的激活所致。佛波醇12，13-二丁酸盐使EIPA敏感的内流减少48%，失活的4α-佛波醇12，13-十二酸对此无影响，而PKC抑制剂鞘氨醇逆转了这一作用。因此，VSMC中的Na(+)-H+交换器是通过PKC以生长依赖的方式进行调节的。
Regulation of intracellular pH (pHi) plays an important role in vascular smooth muscle cell (VSMC) contractile tone and growth. We have shown that pHi in proliferating VSMC is more alkaline (7.25) than in growth-arrested cells (7.10). To study the Na(+)-H+ exchanger in the growth-dependent regulation of VSMC pHi, ethylisopropylamiloride (EIPA)-sensitive Na+ influx was measured. Exposure of growth-arrested VSMC to 10% serum initially increased Na+ influx (145% of baseline at 30 min), which then decreased (52% of baseline at 24 h). Serum-induced alterations in the kinetic properties of the Na(+)-H+ exchanger were studied by analysis of its external Na+ binding site properties. Exposure of growth-arrested VSMC to 10% serum for 24 h increased the Km for external Na+ from 54 to 380 mM, with a change in the Vmax from 155 to 199 nmol Na+.mg protein-1.min-1. The change in Km was due to activation of protein kinase C (PKC). Phorbol 12,13-dibutyrate caused a 48% decrease in EIPA-sensitive influx, the inactive 4 alpha-phorbol 12,13-didecanoate had no effect, and the PKC inhibitor sphingosine reversed the effect. Therefore, the Na(+)-H+ exchanger in VSMC is regulated in a growth-dependent manner via PKC.