Barrett P Q, Zawalich K, Rasmussen H
Biochem Biophys Res Commun. 1985 Apr 30;128(2):494-505. doi: 10.1016/0006-291x(85)90074-9.
Protein kinase C activity was found in rabbit renal microvillus membrane vesicles. C-kinase activity was assayed by examining H1 histone phosphorylation using microvillus membrane vesicles dispersed with Triton X. Calcium-activated protein kinase activity was only demonstrable in the presence of phosphatidylserine (PS). With PS (15 micrograms/ml) the Ka for activation by calcium was 1.04 microM. This was reduced to 0.38 microM by addition of diolein (3.75 micrograms/ml). These activations were dose-dependent and their combined synergistic activation could be reproduced by the combination of PS (15 micrograms/ml) and the phorbol ester, TPA (1.17 ng/ml). During microvillus membrane purification, protein kinase C activity enriched 5-fold relative to its activity in the homogenates. The activity was not due to trapped cytosol or adventitious association with microvillus membranes during homogenization. During further purification on sucrose gradients, the C-kinase activity coenriched with brush border and not with basolateral enzyme markers. We conclude that protein kinase C is a normal component of the renal microvillus membrane.
在兔肾微绒毛膜小泡中发现了蛋白激酶C活性。通过使用用曲拉通X分散的微绒毛膜小泡检测H1组蛋白磷酸化来测定C激酶活性。钙激活的蛋白激酶活性仅在磷脂酰丝氨酸（PS）存在下才能显示出来。对于PS（15微克/毫升），钙激活的Ka为1.04微摩尔。加入二油精（3.75微克/毫升）后，该值降至0.38微摩尔。这些激活是剂量依赖性的，并且它们的联合协同激活可以通过PS（15微克/毫升）和佛波酯TPA（1.17纳克/毫升）的组合来重现。在微绒毛膜纯化过程中，蛋白激酶C活性相对于其在匀浆中的活性富集了5倍。该活性不是由于捕获的胞质溶胶或匀浆过程中与微绒毛膜的偶然结合。在蔗糖梯度上进一步纯化期间，C激酶活性与刷状缘共同富集，而不与基底外侧酶标记物共同富集。我们得出结论，蛋白激酶C是肾微绒毛膜的正常组成部分。
