Developmental regulation of type II calcium/calmodulin-dependent kinase isoforms in rat cerebellum.
Developmental regulation of type II calcium/calmodulin-dependent kinase isoforms in rat cerebellum.
复制标题
大鼠小脑中 II 型钙/钙调蛋白依赖性激酶亚型的发育调节。
DOI：
10.1002/neu.480210810
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Vallano,ML
中科院分区：
文献类型：
--
作者：
Vallano,ML
Two distinct isoforms of a Type II calcium/calmodulindependent protein kinase were separated from highspeed supernates (cytosol) of rat neonatal [postnatal day 10 (P10)] and adult [postnatal day 40 (P40)] cerebellum using cation‐exchange chromatography. The isoenzymes contained variable amounts of three subunits of apparent Mr's of 50 kDa (α), 58 kDa (β'), and 60 kDa (β). The specific activity of calmodulin‐dependent kinase (CaM kinase II) in crude homogenates increased sixfold between P10 and P40 using exogenous MAP 2 as substrate. Cytosol from cerebellum at P40 contained a predominant isoform (∼40% of total cytosolic activity) with a 1:5 molar ratio of α:β',β subunits that eluted with 150 mMNaCl (designated 150) and a less abundant isoform (∼20% of total cytosolic activity) containing a 1:8 molar ratio of α:β',β subunits that eluted with 350 mMNaCl (designated 350). In neonatal cerebellum at P10, the relative abundance of the two isoforms was reversed such that ∼50% of the cytosolic calmodulin‐dependent kinase activity was recovered in the 350 isoform, whereas only 20% of the total cytosolic kinase activity was recovered in the 150 isoform. Previous studies indicate that cerebellar granule cells may contain an all β',β isoform of CaM kinase II that lacks α subunit. Thus, to assess the cell‐specific localization of kinase isoforms within cerebellum, cytosol prepared from primary cultures of rat cerebellar granule cells was applied to cation‐exchange chromatography and analyzed for calmodulin‐dependent kinase activity. The cells contained both isoforms of the kinase that were present in fresh tissue suggesting that granule cell‐enriched cultures express all three kinase subunits. The data demonstrate that rat cerebellum contains unique mixtures of CaM kinase II isoenzymes and that their expression is developmentally regulated.
