Gschwendt M, Kielbassa K, Kittstein W, Marks F
German Cancer Research Center, Heidelberg.
FEBS Lett. 1994 Jun 20;347(1):85-9. doi: 10.1016/0014-5793(94)00514-1.
Native protein kinase C delta from porcine spleen is phosphorylated in vitro by the tyrosine kinase src and to a much smaller extent by fyn. The tyrosine phosphorylation of PKC delta is restricted to the activated state of the enzyme, i.e. it occurs only in the presence of an activator, such as TPA or bryostatin. Upon phosphorylation at tyrosine, the apparent molecular weight of PKC delta increases by 6 kDa. Phosphorylation by src induces a stimulation of PKC delta activity apparently exhibiting some substrate selectivity. Other PKC isoenzymes, such as cPKC (alpha, beta, gamma), are not phosphorylated by src or only to a very small extent. This phosphorylation is not dependent on TPA and does not cause an increase in activity and molecular weight of the enzyme.
来自猪脾脏的天然蛋白激酶Cδ在体外被酪氨酸激酶src磷酸化，而被fyn磷酸化的程度要小得多。PKCδ的酪氨酸磷酸化仅限于该酶的激活状态，即仅在存在激活剂（如佛波酯或苔藓抑素）时发生。酪氨酸磷酸化后，PKCδ的表观分子量增加6 kDa。src介导的磷酸化诱导PKCδ活性增强，显然表现出一定的底物选择性。其他PKC同工酶，如传统PKC（α、β、γ），不被src磷酸化或仅被磷酸化的程度非常小。这种磷酸化不依赖于佛波酯，也不会导致该酶的活性和分子量增加。
