Protein phosphatase type 2C active at physiological Mg2+:: stimulation by unsaturated fatty acids
Protein phosphatase type 2C active at physiological Mg2+:: stimulation by unsaturated fatty acids
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DOI：
10.1016/s0014-5793(98)01237-x
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发表时间：
1998-10-23
期刊：
影响因子：
3.5
通讯作者：
Hermesmeier, J
中科院分区：
文献类型：
--
作者：
Klumpp, S;Selke, D;Hermesmeier, J
迄今为止，2C型丝氨酸/苏氨酸蛋白磷酸酶（PP2C）需要非生理性的大量Mg2+离子才能发挥活性。激活剂和抑制剂不可用，靶向亚基未知。通过对牛视网膜中PP2C同工酶的调控研究，我们发现添加单不饱和脂肪酸和多不饱和脂肪酸可显著提高PP2C的活性。激活在低Mg2+水平下最为明显（0.5 mM花生四烯酸在0.7 mM Mg2+水平下对PP2C α的刺激为10倍）。PP2C β的敏感性降低了30-50%，首次揭示了PP2C同工酶之间的酶学差异。不饱和脂肪酸与生理Mg2+浓度结合导致PP2C活性远远超过其他方法获得的去磷酸化率。这表明PP2C活性在过去被严重低估，在脂肪酸存在下，Ca2+离子在微摩尔范围内具有抑制作用。我们得出结论，不饱和脂肪酸可能在PP2C活性的调节中发挥作用。(C) 1998年欧洲生化学会联合会。
Type 2C serine/threonine protein phosphatases (PP2C) so far require unphysiologically large amounts of Mg2+ ions for activity. Activators and inhibitors are not available, targeting subunits unknown. Studying the regulation of PP2C isozymes in bovine retinae, we found that the activity of PP2C increased specifically by the addition of mono- and polyunsaturated fatty acids. Activation was most pronounced at low Mg2+ levels (10-fold stimulation of PP2C alpha by 0.5 mM arachidonic acid at 0.7 mM Mg2+). Sensitivity of PP2C beta was 30-50% less, revealing for the first time enzymatic differences among the PP2C isozymes, Combining unsaturated fatty acids with physiological Mg2+ concentrations resulted in PP2C activity that by far exceeded the dephosphorylation rates obtained otherwise. This suggests that PP2C activity has been severely underestimated in the past, In the presence of fatty acids, Ca2+ ions became inhibitory in the micromolar range. We conclude that unsaturated fatty acids may play a role in the regulation of PP2C activity. (C) 1998 Federation of European Biochemical Societies.