Hippocalcin mediates calcium-dependent translocation of brain-type creatine kinase (BB-CK) in hippocampal neurons
Hippocalcin mediates calcium-dependent translocation of brain-type creatine kinase (BB-CK) in hippocampal neurons
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DOI：
10.1016/j.bbrc.2012.10.125
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发表时间：
2012-12-14
影响因子：
3.1
通讯作者：
Takamatsu, Ken
中科院分区：
文献类型：
--
作者：
Kobayashi, Masaaki;Hamanoue, Makoto;Takamatsu, Ken
海马钙蛋白（Hpca）是一种钙离子结合蛋白，在神经元中表达，并有助于神经元的可塑性。我们从大鼠脑中纯化了一个48 kDa的Hpca相关蛋白，并鉴定其为肌酸激酶B（CK B）亚基，其构成脑型肌酸激酶（BB-CK）。Hpca特异性结合CKB在钙离子依赖的方式，但不肌型肌酸激酶M亚基。Hpca的N端区域是与CKB结合所必需的。Hpca介导的CKB（约占总肌酸激酶活性的10-15%）的Ca 2+依赖性部分易位至细胞膜。Hpca的N-豆蔻酰化对膜转运至关重要，但对与CKB的结合不重要。在培养的海马神经元中，离子霉素处理导致Hpca和CKB邻近质膜的共定位。这些结果表明，Hpca与BB-CK，并一起易位到膜室中的钙离子依赖性的方式。(C)2012 Elsevier Inc. All rights reserved.
Hippocalcin (Hpca) is a Ca2+-binding protein that is expressed in neurons and contributes to neuronal plasticity. We purified a 48 kDa Hpca-associated protein from rat brain and identified it to be the creatine kinase B (CKB) subunit, which constitutes brain-type creatine kinase (BB-CK). Hpca specifically bound to CKB in a Ca2+-dependent manner, but not to the muscle-type creatine kinase M subunit. The N-terminal region of Hpca was required for binding to CKB. Hpca mediated Ca2+-dependent partial translocation of CKB (approximately 10-15% of total creatine kinase activity) to membranes. N-myristoylation of Hpca was critical for membrane translocation, but not for binding to CKB. In cultured hippocampal neurons, ionomycin treatment led to colocalization of Hpca and CKB adjacent to the plasma membrane. These results indicate that Hpca associates with BB-CK and that together they translocate to membrane compartments in a Ca2+-dependent manner. (C) 2012 Elsevier Inc. All rights reserved.