Subcellular localization of adenosine kinase in mammalian cells: The long isoform of AdK is localized in the nucleus
Subcellular localization of adenosine kinase in mammalian cells: The long isoform of AdK is localized in the nucleus
复制标题
DOI：
10.1016/j.bbrc.2009.07.106
复制
发表时间：
2009-10-09
影响因子：
3.1
通讯作者：
Gupta, Radhey S.
中科院分区：
文献类型：
--
作者：
Cui, Xianying Amy;Singh, Bhag;Gupta, Radhey S.
已在哺乳动物生物体中鉴定了腺苷激酶（AdK）的两种同种型，其中长同种型（AdK-long）在N-末端（NTS）含有额外的20-21个氨基酸。这些亚型的亚细胞定位是未知的，它们不包含可识别的靶向序列。免疫荧光标记的哺乳动物细胞表达要么只有AdK长或两种亚型与AdK特异性抗体显示，只有核标记或核和细胞质标记，分别。AdK-长和-短亚型在C-末端与c-myc表位融合，也分别位于细胞核和细胞质中。AdK-长NTS与绿色荧光蛋白的融合也导致其核定位。AdK-long NTS含有一组保守氨基酸（PKPKKLKVE）。用AA或AD替换该序列中的KK废除了其核定位能力，表明该簇可能充当核定位信号。细胞核中的AdK可能是维持甲基化反应所必需的。(C)2009 Elsevier Inc. All rights reserved.
Two isoforms of adenosine kinase (AdK) have been identified in mammalian organisms with the long isoform (AdK-long) containing extra 20-21 amino acids at the N-terminus (NTS). The subcellular localizations of these isoforms are not known and they contain no identifiable targeting sequence. Immunofluorescence labeling of mammalian cells expressing either only AdK-long or both isoforms with AdK-specific antibody showed only nuclear labeling or both nucleus and cytoplasmic labeling, respectively. The AdK-long and -short isoforms fused at the C-terminus with c-myc epitope also localized in the nucleus and cytoplasm, respectively. Fusion of the AdK-long NTS to green fluorescent protein also resulted in its nuclear localization. AdK-long NTS contains a cluster of conserved amino acids (PKPKKLKVE). Replacement of KK in this sequence with either AA or AD abolished its nuclear localization capability, indicating that this cluster likely serves as a nuclear localization signal. AdK in nucleus is likely required for sustaining methylation reactions. (C) 2009 Elsevier Inc. All rights reserved.