Identification of calcium-calmodulin multifunctional protein kinase II in rabbit kidney.
Identification of calcium-calmodulin multifunctional protein kinase II in rabbit kidney.
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DOI：
10.1038/ki.1990.167
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发表时间：
1990-07
影响因子：
19.6
通讯作者：
R. Hanley;S. Shenolikar;J. Pollack;D. Steplock;E. Weinman
中科院分区：
文献类型：
--
作者：
R. Hanley;S. Shenolikar;J. Pollack;D. Steplock;E. Weinman
兔肾钙调素多功能蛋白激酶II的鉴定。最近的研究表明，钙/钙调素依赖的多功能蛋白激酶II(CaM-KII)抑制了兔肾脏近曲小管刷状缘膜上重组的Na+-H+交换。本研究通过Northern RNA杂交证实CaM-KII在兔肾和近曲小管细胞中的存在，并用合成肽底物选择性酶促法检测CaM-KII的信使RNA(MRNA)，以评价这一发现的生理学意义。兔肾皮质和髓质总RNA与大鼠脑CaM-KII基因的杂交，以及兔肾近曲小管浓缩悬液的杂交，均观察到一条4.9kb的单链RNA。用合成肽底物代表CaM-KII在糖原合成酶上的磷酸化位点的酶分析表明，兔肾皮质(比活性为662±127nmol.min-1·mg蛋白-1)和近曲小管细胞(546±77nmol.min-1·mg蛋白-1)都有钙-钙调蛋白依赖性蛋白激酶活性。这些数据证实了CaM-KII在兔肾脏中的存在，并提示该酶在控制肾脏电解质转运中的作用。
Identification of calcium-calmodulin multifunctional protein kinase II in rabbit kidney. Recent studies have demonstrated that calcium/ calmodulin-dependent multifunctional protein kinase II (CaM-KII) inhibits the reconstituted Na+-H+exchanger from the brush border membrane of proximal convoluted tubule of the rabbit kidney. The present studies were undertaken to evaluate the physiological relevance of this finding by establishing the presence of CaM-KII in rabbit kidney and proximal convoluted tubule cells by Northern RNA hybridization analysis to demonstrate the messenger RNA (mRNA) for CaM-KII and by a selective enzymatic assay of CaM-KII using a synthetic peptide substrate. A single 4.9 Kb mRNA was observed on hybridization of total RNA from rabbit kidney cortex and medulla and from an enriched suspension of rabbit kidney proximal convoluted tubules with a cDNA for rat brain CaM-KII. An enzyme assay using a synthetic peptide substrate representing the site phosphorylated by CaM-KII on glycogen synthase demonstrated calcium-calmodulin dependent protein kinase activity in both rabbit kidney cortex (specific activity of 662 ± 127 nmol · min-1· mg protein-1) and proximal tubule cells (546 ± 77 nmol · min-1· mg protein-1). These data establish the presence of CaM-KII in the rabbit kidney, and suggest a role for this enzyme in the control of renal electrolyte transport.