Characterization of protein phosphatase 2A acting on phosphorylated plasma membrane aquaporin of tulip petals
Characterization of protein phosphatase 2A acting on phosphorylated plasma membrane aquaporin of tulip petals
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DOI：
10.1271/bbb.68.1170
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发表时间：
2004-05-01
影响因子：
1.6
通讯作者：
Shibata, H
中科院分区：
文献类型：
--
作者：
Azad, AK;Sawa, Y;Shibata, H
从郁金香花瓣中分离得到的蛋白磷酸酶全型酶（38、65和75 kDa）和游离催化亚基（38 kDa）经免疫学和生化鉴定为蛋白磷酸酶2A （PP2A）。质膜水通道蛋白（PM-AQP）由郁金香花瓣制备，体外磷酸化，并作为纯化PP2A制剂的底物。虽然这两种酶制剂在20℃下都能使磷酸化的PM-AQP去磷酸化，但只有全型酶制剂在5℃下对磷酸化的PM-AQP有更高的底物特异性，这表明郁金香花瓣中PM-AQP的低温依赖性去磷酸化需要调节亚基。
A protein phosphatase holo-type enzyme (38, 65, and 75 kDa) preparation and a free catalytic subunit (38 kDa) purified from tulip petals were characterized as protein phosphatase 2A (PP2A) by immunological and biochemical approaches. The plasma membrane containing the putative plasma membrane aquaporin (PM-AQP) was prepared from tulip petals, phosphorylated in vitro, and used as the substrate for both of the purified PP2A preparations. Although both preparations dephosphorylated the phosphorylated PM-AQP at 20degreesC, only the holo-type enzyme preparation acted at 5degreesC on the phosphorylated PM-AQP with higher substrate specificity, suggesting that regulatory subunits are required for low temperature-dependent dephosphorylation of PM-AQP in tulip petals.