Correas I, Díaz-Nido J, Avila J
Centro de Biología Molecular, Facultad de Ciencias, Universidad Autónoma, Madrid, Spain.
J Biol Chem. 1992 Aug 5;267(22):15721-8.
We have analyzed the in vitro phosphorylation of tau protein by Ca2+/calmodulin-dependent protein kinase, casein kinase II, and proline-directed serine/threonine protein kinase. These kinases phosphorylate tau protein in sites localized in different regions of the molecule, as determined by peptide mapping analyses. Focusing on the phosphorylation of tau by protein kinase C, it was calculated as an incorporation of 4 mol of phosphate/mol of tau. Limited proteolysis assays suggest that the phosphorylation sites could be located within the tubulin-binding domain. Direct phosphorylation of synthetic peptides corresponding to the cysteine-containing tubulin-binding region present in both fetal and adult tau isoforms demonstrates that serine 313 is modified by protein kinase C. Phosphorylation of the synthetic peptide by protein kinase C diminishes its binding to tubulin, as compared with the unphosphorylated peptide.
我们分析了钙离子/钙调蛋白依赖性蛋白激酶、酪蛋白激酶II和脯氨酸定向丝氨酸/苏氨酸蛋白激酶对tau蛋白的体外磷酸化作用。通过肽图谱分析确定，这些激酶在tau蛋白分子不同区域的位点上使其磷酸化。聚焦于蛋白激酶C对tau的磷酸化，计算得出每摩尔tau掺入4摩尔磷酸盐。有限蛋白酶解分析表明，磷酸化位点可能位于微管蛋白结合域内。对胎儿和成人tau异构体中存在的含半胱氨酸微管蛋白结合区域对应的合成肽进行直接磷酸化，结果表明丝氨酸313被蛋白激酶C修饰。与未磷酸化的肽相比，蛋白激酶C对合成肽的磷酸化降低了其与微管蛋白的结合。
