Phosphorylation of the protein kinase A catalytic subunit is induced by cyclic AMP deficiency and physiological stresses in the fission yeast, Schizosaccharomyces pombe.
Phosphorylation of the protein kinase A catalytic subunit is induced by cyclic AMP deficiency and physiological stresses in the fission yeast, Schizosaccharomyces pombe.
复制标题
蛋白激酶 A 催化亚基的磷酸化是由裂殖酵母 (Schizosaccharomyces pombe) 中的环 AMP 缺乏和生理应激诱导的。
DOI：
10.1016/j.bbrc.2010.07.139
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发表时间：
2010
影响因子：
3.1
通讯作者：
Marcus,Stevan
中科院分区：
文献类型：
--
作者：
McInnis,Brittney;Mitchell,Jessica;Marcus,Stevan
在裂殖酵母中，环磷酸腺苷(CAMP)依赖的蛋白激酶(PKA)在正常培养条件下并不是维持活性所必需的，这使得该生物成为研究PKA调控机制的理想生物。在这里，我们发现携带腺苷环化酶基因Cyr1缺失的S.pombe细胞比野生型细胞表达明显更高水平的PKA催化亚单位Pka1。值得注意的是，在Cyr1Δ细胞中，相当大比例的Pka1蛋白被过度磷酸化，而不是野生型细胞。在Cyr1Δ细胞中，Pka1的过度磷酸化被强烈诱导，在野生型细胞中，葡萄糖饥饿和稳定期应激都不同程度地诱导了Pka1的过度磷酸化，葡萄糖饥饿和稳定期应激与cAMP依赖的蛋白激酶A活性降低有关，而氯化钾胁迫对细胞的适应依赖于蛋白激酶A的活性。有趣的是，在任何测试条件下，携带PKA调节亚单位基因cgs1缺失的Cyr1+或Cyr1ΔS.pombe菌株都没有检测到Pka1的过度磷酸化。我们的结果证明了PKA催化亚单位磷酸化的cAMP非依赖性机制的存在，我们认为这可能是一种在cAMP依赖的活性下调的情况下诱导或维持特定PKA功能的机制。
In the fission yeast, Schizosaccharomyces pombe, cyclic AMP (cAMP)-dependent protein kinase (PKA) is not essential for viability under normal culturing conditions, making this organism attractive for investigating mechanisms of PKA regulation. Here we show that S. pombe cells carrying a deletion in the adenylate cyclase gene, cyr1, express markedly higher levels of the PKA catalytic subunit, Pka1, than wild type cells. Significantly, in cyr1Δ cells, but not wild type cells, a substantial proportion of Pka1 protein is hyperphosphorylated. Pka1 hyperphosphorylation is strongly induced in cyr1Δ cells, and to varying degrees in wild type cells, by both glucose starvation and stationary phase stresses, which are associated with reduced cAMP-dependent PKA activity, and by KCl stress, the cellular adaptation to which is dependent on PKA activity. Interestingly, hyperphosphorylation of Pka1 was not detected in either cyr1+or cyr1Δ S. pombe strains carrying a deletion in the PKA regulatory subunit gene, cgs1, under any of the tested conditions. Our results demonstrate the existence of a cAMP-independent mechanism of PKA catalytic subunit phosphorylation, which we propose could serve as a mechanism for inducing or maintaining specific PKA functions under conditions in which its cAMP-dependent activity is downregulated.