人类蛋白激酶C的激活和底物特异性α和zeta同功酶。
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科赫兄弟G,无角的R, Meyer D,拥抱H, Marme D, Sarre TF
人类蛋白激酶C的激活和底物特异性α和zeta同功酶。
欧元。1993年9月1日,216 (2):597 - 606。
- PubMed ID
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8375396 (在PubMed]
- 文摘
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蛋白激酶C (PKC),一类丝氨酸/苏氨酸激酶激活钙离子和/或磷脂,参与各种各样的细胞过程,如增殖,分化和分泌。九PKC已知基因家族的成员;这些是在真核细胞中差异表达,可以划分为两个群体:Ca(2 +)端依赖(古典)PKC同功酶α,β,β二世和γ,和Ca(2 +)独立neoPKC同功酶三角洲,ε,ζ,埃塔组织和θ。详细这些PKC同功酶的生化特性描述是一个先决条件的说明,不同的角色在细胞信号转导。在这项研究中,我们报告的克隆人类PKC-zeta cDNA表达的重组baculovirus-infected昆虫细胞的局部净化PKC-zeta同工酶。人类PKC相比,高纯度α,古典PKC子群的代表,纯化PKCζ特征对催化剂的要求,底物特异性,蛋白水解对PKC抑制剂激活和敏感性。与PKCα,PKCζ展品的本构激酶活性Ca2 +的独立,磷脂酰丝氨酸和甘油二酯。花生四烯酸单独或结合gamma-linolenic酸和磷脂酰丝氨酸稍微加强PKCζ活动。在经典的PKC活化剂磷脂酰丝氨酸/甘油二酯,PKCα磷酸化PKC-alpha pseudosubstrate-derived肽,epidermal-growth-factor-receptor-derived肽,组蛋白III-S和髓鞘碱性蛋白在同等程度上,同时PKCζ磷酸化PKC-alpha-derived肽。然而,花生四烯酸大大减少PKC-alpha活动向epidermal-growth-factor-receptor-derived肽,组蛋白III-S和髓磷脂碱性蛋白,但提高PKC-zeta活动向PKC-alpha-derived肽。 These results indicate a possible modulation of substrate specificity of these two PKC isoenzymes by (the binding of) different activators (to their regulatory domains). In the case of PKC zeta, this finding is strengthened by the fact that the epidermal growth factor receptor-derived peptide, which is not a substrate for the holoenzyme, is significantly phosphorylated by a protein fragment generated by limited proteolysis and comprising only the kinase domain. Furthermore, PKC zeta, in contrast to PKC alpha, is insensitive to PKC inhibitors known to interfere either with the regulatory or the catalytic domain and cannot be activated by phorbol ester treatment of NIH 3T3 cells or insect cells, overexpressing the respective PKC isoenzyme. The potential implications of these findings on the mechanism(s) of activation and the substrate specificity of PKC zeta are discussed.