Protein phosphatase type 2C active at physiological Mg2+: stimulation by unsaturated fatty acids

FEBS Letters

Selke, Dagmar¹  Hermesmeier, Jan¹  Klumpp, Susanne¹ 

[1] Universität, Institut für Pharmazeutische Chemie, Abteilung Biochemie, Marbacher Weg 6, 35032 Marburg, Germany

关键词: Arachidonic acid;    Calcium;    Enzyme activation;    Magnesium;    Protein phosphatase;    Protein phosphorylation;    PP1;    PP2A;    and PP2C;    types 1;    2A;    and 2C eukaryotic serine/threonine-specific protein phosphatases;    BSA;    bovine serum albumin;   

DOI  :  10.1016/S0014-5793(98)01237-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 PP2Cα by 0.5 mM arachidonic acid at 0.7 mM Mg²⁺). Sensitivity of PP2Cβ 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.

【 授权许可】

Unknown