STRUCTURAL BASIS FOR SPECIES-SPECIFIC DIFFERENCES IN THE PHOSPHORYLATION OF NA,K-ATPASE BY PROTEIN-KINASE-C
STRUCTURAL BASIS FOR SPECIES-SPECIFIC DIFFERENCES IN THE PHOSPHORYLATION OF NA,K-ATPASE BY PROTEIN-KINASE-C
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DOI：
10.1074/jbc.270.23.14072
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发表时间：
1995-06-09
影响因子：
4.8
通讯作者：
SWEADNER, KJ
中科院分区：
文献类型：
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作者：
FESCHENKO, MS;SWEADNER, KJ
有大量证据表明蛋白激酶在Na，K-ATP酶活性的调节中起作用，但Na，K-ATP酶亚基的直接激酶磷酸化的特征仍不清楚。在大鼠α 1中有36个位点可以作为蛋白激酶C基序。在这里，我们已经使用蛋白质片段与胰蛋白酶本地化的网站磷酸化的大鼠Na，K-ATP酶α 1亚基的N末端的前32个氨基酸内，然后使用直接测序的磷酸化蛋白质，以确定两个候选丝氨酸残基被修改。结果是，最多25%的P-32被发现在Ser-11上，这是Na，K-ATP酶α 1亚基中非常保守的位点。其余75%或更多的P-32位于Ser-18上，这是许多Na，K-ATP酶α亚基序列中不存在的位点。这就解释了狗和猪α 1亚基被蛋白激酶C磷酸化的程度比大鼠α 1低得多。这也可能与蛋白激酶C对Na，K-ATP酶的其他已知物种特异性作用有关。
There is considerable evidence that protein kinases play a role in regulation of the activity of the Na,K-ATPase, but the characteristics of direct kinase phosphorylation of Na,K-ATPase subunits are still not well understood. There are 36 sites that could qualify as protein kinase C motifs in rat alpha 1. Here we have used protein fragmentation with trypsin to localize the site of phosphorylation of the rat Na,K-ATPase alpha 1 subunit to within the first 32 amino acids of the N terminus and then used direct sequencing of the phosphorylated protein to determine which of two candidate serine residues was modified. The result was that at most 25% of the P-32 was found on Ser-11, a site that is well conserved in Na,K-ATPase alpha 1 subunits. The remaining 75% or more of the P-32 was found on Ser-18, a site that is absent in many Na,K-ATPase alpha subunit sequences. This accounts for the observation that dog and pig alpha 1 subunits can be phosphorylated by protein kinase C only to much lower levels than can rat alpha 1. It is also likely to be relevant to other known species specific effects of protein kinase C on Na,K-ATPase.