Uemura A, Naito Y, Matsubara T, Hotta N, Hidaka H
Department of Pharmacology, Third Department of Internal Medicine, Nagoya University School of Medicine, Tsurumai 65, Showa-ku, Nagoya, 466-8550, Japan.
Biochem Biophys Res Commun. 1998 Aug 19;249(2):355-60. doi: 10.1006/bbrc.1998.9154.
Members of the Ca2+/calmodulin dependent protein kinase (CaMK) family and a CaMK cascade have been identified and well characterized in the brain, but little is known about their equivalents in the heart. Thus only CaMKII and its function have been reported so far. Therefore, we purified and characterized CaMKI and CaMK kinase (CaMKK) as an associated activator from the hog heart for the first time. The heart CaMKI was revealed to be the alpha isoform of brain CaMKI with a molecular weight of 41 kDa to phosphorylate cardiac phospholamban peptide, and to exhibit autophosphorylation requiring CaMKK. Heart CaMKK was found as a 67 kDa band and proved to be a different kinase from that in brain. These data indicate the existence of a heart specific CaMK cascade, consisting of CaMKI and CaMKK, along with CaMKII, which should be taken into account in any consideration of Ca2+ signal transduction.
钙离子/钙调蛋白依赖性蛋白激酶（CaMK）家族成员和CaMK级联反应已在大脑中得到鉴定和充分表征，但人们对其在心脏中的对应物了解甚少。因此，迄今为止仅报道了CaMKII及其功能。因此，我们首次从猪心脏中纯化并鉴定了CaMKI和作为相关激活剂的CaMK激酶（CaMKK）。心脏CaMKI被发现是大脑CaMKI的α异构体，分子量为41 kDa，可磷酸化心脏受磷蛋白肽，并表现出需要CaMKK的自身磷酸化。心脏CaMKK表现为一条67 kDa的条带，并且被证明是与大脑中的激酶不同的激酶。这些数据表明存在一个心脏特异性的CaMK级联反应，由CaMKI、CaMKK以及CaMKII组成，在任何关于Ca2+信号转导的考虑中都应予以考虑。
