Translated Alu sequence determines nuclear localization of a novel catalytic subunit of casein kinase 2
Translated Alu sequence determines nuclear localization of a novel catalytic subunit of casein kinase 2
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DOI：
10.1152/ajpcell.00070.2002
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发表时间：
2002-08-01
影响因子：
5.5
通讯作者：
Stockert, RJ
中科院分区：
文献类型：
--
作者：
Hilgard, P;Huang, TM;Stockert, RJ
酪蛋白激酶2（CK 2）是一种组成型表达于所有真核组织中的四聚体酶。据报道，催化亚基的两种已知亚型CK 2 α和CK 2 α ′具有不同的组织依赖性亚细胞分布。我们最近描述了催化亚基的第三种亚型，命名为CK 2 α，其在肝脏中高度表达。HuH-7人肝癌细胞组分的免疫印迹分析以及免疫荧光显微镜检查显示，CK 2 α”仅定位于细胞核，并优先与核基质相关。CK 2 α和CK 2 α '存在于细胞核、细胞膜和胞质中。从CK 2 alpha”序列中删除羧基末端32个氨基酸导致截短的绿色荧光蛋白融合蛋白从核基质中释放并重新分布到细胞核和细胞质中。羧基末端对于核滞留是必需的但不是充分的，这表明CK 2 α核定位的潜在机制依赖于由羧基末端序列指导的全酶的二级结构。
Casein kinase 2 (CK2) is a tetrameric enzyme constitutively expressed in all eukaryotic tissues. The two known isoforms of the catalytic subunit, CK2alpha and CK2alpha', have been reported to have distinct tissue-dependent subcellular distributions. We recently described a third isoform of the catalytic subunit, designated CK2alpha", which is highly expressed in liver. Immunoblot analysis of HuH-7 human hepatoma cell fractions as well as immunofluorescent microscopy revealed that CK2alpha" was exclusively localized to the nucleus and preferentially associated with the nuclear matrix. CK2alpha and CK2alpha' were found in nuclear, membrane, and cytosolic compartments. Deletion of the carboxy-terminal 32 amino acids from the CK2alpha" sequence resulted in release of the truncated green fluorescent protein fusion protein from the nuclear matrix and redistribution to both the nucleus and the cytoplasm. Demonstration that the carboxy terminus is necessary but not sufficient for nuclear retention indicates that the underlying mechanism of CK2alpha" nuclear localization is dependent on the secondary structure of the holoenzyme directed by the carboxy-terminal sequence.