Lau Y S
Department of Pharmacology, Creighton University Medical School, Omaha, Nebraska 68178-0225.
Neurochem Res. 1990 Mar;15(3):265-72. doi: 10.1007/BF00968670.
The characteristics of endogenous Ca2+/calmodulin (CaM)- and Ca2+/phosphatidylserine (PS)-stimulated phosphorylated proteins in the striatum of rat were partially determined and compared in this study. The Ca2+/CaM-dependent phosphoproteins were associated with serine and threonine residues. The sensitivity of these proteins for phosphorylation by Ca2+/CaM was not affected by pretreatment of tissue with Ca2+ chelating agent, EGTA or with non-ionic detergent, Triton X-114. Triton X-114 phase separation experiments revealed that these Ca2+/CaM-dependent phosphoproteins were partitioned in the detergent rich phase suggesting that they are integral proteins of the striatal membrane. On the other hand, the Ca2+/PS-dependent phosphorylated proteins were primarily associated with the serine residue. Phosphorylation of these proteins by Ca2+/PS were abolished after the treatment with EGTA or Triton X-114. These results suggest that Ca2+/PS-dependent striatal phosphoproteins are biochemically unstable in maintaining their state of phosphorylation.
本研究部分测定并比较了大鼠纹状体内内源性Ca2+/钙调蛋白（CaM）和Ca2+/磷脂酰丝氨酸（PS）刺激的磷酸化蛋白的特征。Ca2+/CaM依赖性磷蛋白与丝氨酸和苏氨酸残基相关。这些蛋白被Ca2+/CaM磷酸化的敏感性不受用Ca2+螯合剂EGTA或非离子去污剂Triton X-114预处理组织的影响。Triton X-114相分离实验表明，这些Ca2+/CaM依赖性磷蛋白分布在富含去污剂的相中，表明它们是纹状体膜的整合蛋白。另一方面，Ca2+/PS依赖性磷酸化蛋白主要与丝氨酸残基相关。用EGTA或Triton X-114处理后，这些蛋白被Ca2+/PS的磷酸化作用被消除。这些结果表明，Ca2+/PS依赖性纹状体磷蛋白在维持其磷酸化状态方面在生化上不稳定。
