Interaction of protein kinase C with membranes is regulated by Ca2+, phorbol esters, and ATP.
Interaction of protein kinase C with membranes is regulated by Ca2+, phorbol esters, and ATP.
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蛋白激酶 C 与膜的相互作用受 Ca2+、佛波酯和 ATP 的调节。
DOI：
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发表时间：
1985
影响因子：
4.8
通讯作者：
N. Sahyoun
中科院分区：
文献类型：
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作者：
M. Wolf;P. Cuatrecasas;N. Sahyoun
蛋白激酶C活性的生理调节需要其与细胞膜的相互作用。我们最近表明，结合酶的质膜是由Ca 2+控制，而酶激活剂，如佛波醇酯，调节膜结合和酶的活性。在这里，我们描述了控制蛋白激酶C从质膜上解离的因素。在没有佛波醇酯的情况下，解离反应是快速的，并且通过在0.1和1 μ M之间改变Ca 2+浓度来确定。然而，4-β-佛波醇12，13-二丁酸酯的存在大大降低了响应于Ca 2+耗尽的酶释放;佛波醇酯本身的去除允许有效的膜-酶解离。由佛波醇酯引起的膜蛋白激酶C复合物的稳定可以被ATP逆转，其核苷酸的表观Km为6.5 μ M。ATP效应需要MgCl 2，并且不能由其他核苷酸或不可水解的类似物再现，这表明可能涉及ATP依赖性磷酸化反应。4-β-佛波醇12，13-二丁酸酯似乎通过将Ca 2+的表观Km降低至约15 nM来稳定膜-酶结合，而ATP通过将Ca 2+的Km增加至约760 nM来逆转佛波醇酯效应。此外，由Ca 2+依赖性酶-膜解离显示的负协同性的强程度与蛋白激酶C上存在多个相互作用的Ca 2+结合位点一致。
Physiologic regulation of protein kinase C activity requires its interaction with cellular membranes. We have recently shown that binding of the enzyme to plasma membranes is controlled by Ca2+, whereas enzyme activators, like phorbol esters, regulate both membrane binding and enzyme activity. Here we describe the factors which control the dissociation of protein kinase C from the plasma membrane. In the absence of phorbol esters, the dissociation reaction is rapid and is determined by varying the Ca2+ concentration between 0.1 and 1 microM. However, the presence of 4-beta-phorbol 12,13-dibutyrate greatly reduces enzyme release in response to Ca2+ depletion; removal of the phorbol ester itself permits efficient membrane-enzyme dissociation. The stabilization of the membrane-protein kinase C complex by phorbol esters can be reversed by ATP with an apparent Km for the nucleotide of 6.5 microM. The ATP effect requires MgCl2 and cannot be reproduced by other nucleotides or by a nonhydrolyzable analogue, suggesting that an ATP-dependent phosphorylation reaction may be involved. 4-beta-Phorbol 12,13-dibutyrate appears to stabilize membrane-enzyme association by reducing the apparent Km for Ca2+ to about 15 nM, whereas ATP reverses the phorbol ester effect by increasing the Km for Ca2+ to about 760 nM. Furthermore, the strong degree of negative cooperativity displayed by the Ca2+-dependent enzyme-membrane dissociation is consistent with the presence of multiple interacting Ca2+-binding sites on protein kinase C.