Activation of protein kinase C isozymes by contractile stimuli in arterial smooth muscle.
Activation of protein kinase C isozymes by contractile stimuli in arterial smooth muscle.
复制标题
动脉平滑肌收缩刺激激活蛋白激酶 C 同工酶。
DOI：
10.1016/0003-9861(92)90281-z
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发表时间：
1992
影响因子：
3.9
通讯作者：
Benscoter,H
中科院分区：
文献类型：
--
作者：
Singer,HA;Schworer,CM;Sweeley,C;Benscoter,H
蛋白激酶C （PKC）被认为参与血管平滑肌（VSM）收缩活动的调节。然而，关于该激酶或该激酶的特异性同工酶在VSM中通过收缩刺激激活的细节知之甚少。作为PKC激活的指标，Ca2+和磷脂依赖性组蛋白IIIS激酶活性在等长收缩颈动脉平滑肌单个条带的颗粒分数中被测量。Phorbol 12,13-二丁酸酯（PDB）增加颗粒部位PKC活性（比静息值增加155%），其时间过程与力发展平行或先于力发展。用激动剂组胺（10−5m）刺激可使力和颗粒部分PKC活性迅速增加，最大时间为2分钟（增加139%），部分持续时间超过45分钟（增加41%）。KCl （109 mm）引起持续的收缩反应，导致颗粒部分PKC活性缓慢增加（45分钟增加124%）。在对任何刺激的反应中，未观察到不依赖于激活剂的组蛋白激酶活性的显著增加。PKCα和PKCβ被确定为主要的Ca2+/磷脂依赖性PKC同工酶。在未受刺激的动脉组织中，免疫检测的同工酶含量（α:β）在颗粒中估计为1:1，在细胞质中估计为1.5:1。在三种收缩刺激中的每一种刺激下，通过免疫印迹评估的PKC颗粒分数含量随着时间的推移而增加，其程度与PKC活性的观察变化相当。与其他收缩刺激相比，PDB对PKCα或-β同工酶的调节没有差异。这些结果表明，不同的收缩刺激能够在功能性平滑肌制备过程中强直激活PKC，并且PKCα和/或-β在调节正常平滑肌收缩活动中的功能作用是一致的。
Protein kinase C (PKC) has been proposed to be involved in the regulation of vascular smooth muscle (VSM) contractile activity. However, little is known in detail about the activation of this kinase or specific isozymes of this kinase by contractile stimuli in VSM. As an index of PKC activation, Ca2+- and phospholipid-dependent histone IIIS kinase activity was measured in the particulate fraction from individual strips of isometrically contracting carotid arterial smooth muscle. Phorbol 12,13-dibutyrate (PDB) increased PKC activity in the particulate fraction (155% over resting value by 15 min) with a time course which paralleled or preceded force development. Stimulation with the agonist histamine (10−5m) resulted in rapid increases in both force and particulate fraction PKC activity which was maximal by 2 min (increase of 139%) and partially sustained over 45 min (increase of 41%). KCl (109 mm), which evokes a sustained contractile response, caused a slow increase (124% by 45 min) in particulate fraction PKC activity. No significant increases in activator-independent histone kinase activity were observed in response to any stimulus tested. PKCα and PKCβ were identified as the principal Ca2+/phospholipid-dependent PKC isozymes expressed in this tissue. In unstimulated arterial tissue, the ratio of immunodetectable isozyme content (α:β) was estimated to be 1:1 in the particulate and 1.5:1 in the cytosolic fractions. Upon stimulation with each of the three contractile stimuli, particulate fraction PKC content assessed by immunoblotting increased with a time course and to an extent comparable to the observed changes in PKC activity. There was no evidence of differential regulation of the PKCα or -β isozymes by PDB compared to the other contractile stimuli. These results indicate that diverse contractile stimuli are capable of tonically activating PKC in preparations of functional smooth muscle, and are consistent with a functional role for PKCα and/ or -β in the regulation of normal smooth muscle contractile activity.