INCREASED PROTEIN-KINASE-C AND ISOZYME REDISTRIBUTION IN PRESSURE-OVERLOAD CARDIAC-HYPERTROPHY IN THE RAT
INCREASED PROTEIN-KINASE-C AND ISOZYME REDISTRIBUTION IN PRESSURE-OVERLOAD CARDIAC-HYPERTROPHY IN THE RAT
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DOI：
10.1161/01.res.75.5.926
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发表时间：
1994-11-01
影响因子：
20.1
通讯作者：
BISHOP, SP
中科院分区：
文献类型：
--
作者：
GU, X;BISHOP, SP
蛋白激酶C（PKC）活性和同工酶分布的压力超负荷诱导的心肌肥厚的发展进行了评估。将3周龄大鼠松散地捆绑在升主动脉上（左心室肥厚[LVH]组）。两周后，当左心室质量比假手术对照组大50%且心脏质量仍快速增加超过正常生长时，测定PKC活性和[H-3]佛波醇12，13-二丁酸酯（PDBu）结合能力。在LVH中，胞浆、膜和核-细胞骨架组分中的PKC活性分别为对照值的119 +/-14%、158 +/-17%和152 +/- 9%（n = 9或10）。[H-3]PDBu结合试验显示LVH胞浆中PKC浓度增加（对照，0.51 +/-0.06pmol/L/mg; LVH，0.78 +/-0.09pmol/L/mg; n = 5; P <0.05）和膜部分（对照，1.33 +/- 0.15; LVH，2.32 +/- 0.39; n = 5; P <0.05）。Scatchard分析表明对照组和LVH组的K-d值无差异。使用PKC亚型特异性抗体的免疫印迹分析显示，Ca 2+依赖性（α和β）和Ca 2+非依赖性（δ，β和ζ）亚型均存在于左心室。与对照值相比，β（1，2）和β（1，2）在膜和核-细胞骨架组分中的浓度以及β（1，2）在胞质溶胶中的浓度增加。PKC-δ仅在核细胞骨架组分中检测到，在LVH中没有变化。PKC-α和-zeta存在于所有三种组分中，但在LVH中没有改变。这些数据表明，PKC活性和浓度增加的LVH的发展过程中的压力超负荷。增加的PKC同工酶主要限于PKC-β（1，2）和PKC-β 2，并且增加主要存在于膜和核细胞骨架组分。
Protein kinase C (PKC) activity and isozyme distribution were evaluated during development of pressure-overload-induced cardiac hypertrophy. Three-week-old rats were loosely banded on the ascending aorta (left ventricular hypertrophy [LVH] group). Two weeks later, when left ventricular mass was 50% greater than in the sham-operated control group and cardiac mass was still rapidly increasing beyond that of normal growth, PKC activity and [H-3]phorbol 12,13-dibutyrate (PDBu) binding capacity were determined. In LVH, PKC activity was 119 +/- 14%, 158 +/- 17%, and 152 +/- 9% of the control value in cytosol, membrane, and nuclear-cytoskeletal fractions, respectively (n = 9 or 10). [H-3]PDBu binding assay revealed increased PKC concentration in LVH cytosolic (control, 0.51 +/- 0.06 pmol/L per milligram; LVH, 0.78 +/- 0.09 pmol/L per milligram; n = 5; P < .05) and membrane fractions (control, 1.33 +/- 0.15; LVH, 2.32 +/- 0.39; n = 5; P < .05). Scatchard analysis indicated no difference in K-d values between control and LVH groups. Immunoblot analysis using PKC isoform-specific antibodies showed that both Ca2+-dependent (alpha and beta) and Ca2+-independent (delta, epsilon, and zeta) isoforms were present in the left ventricle. Compared with the control value, there was increased concentration in the membrane and nuclear-cytoskeletal fractions for beta(1,2) and epsilon and in the cytosol for beta(1,2). PKC-delta could be detected only in the nuclear-cytoskeletal fraction and was not changed in LVH. PKC-alpha and -zeta were present in all three fractions but were not altered in LVH. These data indicate that PKC activity and concentration increase during development of LVH induced by pressure overload. The increased PKC isozymes were mainly limited to PKC-beta(1,2) and PKC-epsilon, and the increase was present mainly in the membrane and nuclear-cytoskeletal fractions.