Protein phosphatase 2A is the main phosphatase involved in the regulation of protein kinase B in rat adipocytes
Protein phosphatase 2A is the main phosphatase involved in the regulation of protein kinase B in rat adipocytes
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DOI：
10.1016/s0898-6568(01)00238-8
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发表时间：
2002-03-01
影响因子：
4.8
通讯作者：
Degerman, E
中科院分区：
文献类型：
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作者：
Resjö, S;Göransson, O;Degerman, E
在脂肪细胞中，蛋白激酶B（PKB）被认为是磷酸化磷酸二酯酶3 B（PDE 3 B）的酶，磷酸二酯酶3 B是胰岛素抗脂肪分解信号通路中的关键酶。为了筛选PKB磷酸酶，使用离子交换色谱分离脂肪细胞匀浆并分析PKB磷酸酶活性。PKB磷酸酶活性洗脱为一个主峰，与丝氨酸/苏氨酸磷酸酶（PP）2A结合。此外，将脂肪细胞与PP抑制剂一起孵育。用1 μ M冈田酸孵育脂肪细胞可抑制PP 2A活性75%和PP 1活性仅17%，而1 μ M互变霉素可抑制PP 1活性54%和PP 2A活性仅7%。冈田酸，而不是互变霉素，诱导激活的PKB α和PKB β。最后，PP 2A亚基在几个亚细胞区室中被发现，包括质膜（PM），其中PKB的磷酸化被认为发生。总之，我们的结果表明PP 2A是脂肪细胞中PKB去磷酸化的主要磷酸酶。(C)2002年爱思唯尔科技有限公司All rights reserved.
In adipocytes, protein kinase B (PKB) has been suggested to be the enzyme that phosphorylates phosphodiesterase 3B (PDE3B), a key enzyme in insulin's antilipolytic signalling pathway. In order to screen for PKB phosphatases, adipocyte homogenates were fractionated using ion-exchange chromatography and analysed for PKB phosphatase activities. PKB phosphatase activity eluted as one main peak, which cocluted with serine/threonine phosphatases (PP)2A. In addition, adipocytes were incubated with inhibitors of PP. Incubation of adipocytes with 1 muM okadaic acid inhibited PP2A by 75% and PP I activity by only 17%, while 1 muM tautomycin inhibited PP1 activity by 54% and PP2A by only 7%. Okadaic acid, but not tautomycin, induced the activation of both PKBalpha and PKBbeta. Finally, PP2A subunits were found in several subcellular compartments, including plasma membranes (PM) where the phosphorylation of PKB is thought to occur. In summary, our results suggest that PP2A is the principal phosphatase that dephosphorylates PKB in adipocytes. (C) 2002 Elsevier Science Inc. All rights reserved.