Phosphorylation regulated by protein kinase A and alkaline phosphatase play positive roles in μ-calpain activity
Phosphorylation regulated by protein kinase A and alkaline phosphatase play positive roles in μ-calpain activity
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DOI：
10.1016/j.foodchem.2018.01.103
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发表时间：
2018-06-30
期刊：
影响因子：
8.8
通讯作者：
Zhang, Dequan
中科院分区：
文献类型：
--
作者：
Du, Manting;Li, Xin;Zhang, Dequan
本研究的目的是确定在不同的Ca 2+浓度的磷酸化/去磷酸化调节蛋白激酶A（PKA）和碱性磷酸酶（AP）的μ-钙蛋白酶活性的影响。用0.01、0.05、0.1和1 mM Ca 2+的AP或PKA处理μ-Calpain。在孵育过程中，AP组的pH值下降，但在对照组和PKA组中保持稳定。除0.01和0.1mM Ca ~（2+）孵育20 min以上的样品外，PKA孵育的μ-calpain的自溶程度高于对照组，但低于AP组。μ-钙蛋白酶α-螺旋结构的含量随磷酸化水平的升高而增加。在丝氨酸255、256、476、417和420处鉴定了mu-钙蛋白酶的磷酸化。PKA催化位于结构域II和III的丝氨酸255、256和476处的μ-钙蛋白酶磷酸化，正调节μ-钙蛋白酶活性。这些数据表明，去磷酸化和PKA磷酸化正调节μ-钙蛋白酶活性，这是有限的增加Ca 2+浓度。
This study was aimed to determine the effect of phosphorylation/dephosphorylation regulated by protein kinase A (PKA) and alkaline phosphatase (AP) on mu-calpain activity at different Ca2+ concentrations. mu-Calpain was treated with AP or PKA at 0.01, 0.05, 0.1 and 1mM Ca2+. The pH value decreased in the AP group but remained stable in the control and PKA groups during incubation. Except samples incubated at 0.01 and 0.1mM Ca2+ for more than 20 min, mu-calpain incubated with PKA showed a higher degree of autolysis than control, but lower than the AP group. The content of a-helix structure of mu-calpain increased as phosphorylation level rose. Phosphorylation of mu-calpain at serine 255, 256, 476, 417 and 420 was identified. PKA catalyzed mu-calpain phosphorylation at serine 255, 256 and 476, located at domains II and III, positively regulated mu-calpain activity. These data demonstrated that dephosphorylation and PKA phosphorylation positively regulated mu-calpain activity, which was limited by increased Ca2+ concentration.