A-kinase-interacting protein localizes protein kinase A in the nucleus
A-kinase-interacting protein localizes protein kinase A in the nucleus
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DOI：
10.1073/pnas.0408608102
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发表时间：
2005-01-11
影响因子：
11.1
通讯作者：
Taylor, SS
中科院分区：
文献类型：
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作者：
Sastri, M;Barraclough, DM;Taylor, SS
蛋白激酶A（PKA）催化（C）亚基氨基末端的遗传变异性和共价修饰表明，它可能有助于蛋白质-蛋白质相互作用和/或定位。通过酵母双杂交筛选，我们鉴定了PKA相互作用蛋白（AKIP 1），其结合PKA的C亚基的氨基末端（残基1-39）。相互作用定位于C亚基的A螺旋（残基14-39）和AKIP 1的羧基末端。AKIP 1因此定义PKA的氨基末端A螺旋作为蛋白质相互作用基序。在正常乳腺（Hs 578 Bst）和HeLa细胞中，AKIP 1以斑点形式存在于细胞核中。鉴定了核定位信号（Arg-14和Arg-15）。在刺激与毛喉素，HeLa细胞表达AKIP 1积累了更高水平的内源性C亚基在细胞核中。AKIP 1的羧基末端的缺失或C亚基的残基1-39的过表达废除了活化的内源性C亚基的核定位。因此，AKIP 1描述了一种PKA相互作用蛋白，其可以通过与调节亚基相互作用的A激酶锚定蛋白不同的机制来有助于定位。
The genetic variability and covalent modifications associated with the amino terminus of the protein kinase A (PKA) catalytic (C) subunit suggest that it may contribute to protein-protein interactions and/or localization. By using a yeast two-hybrid screen, we identified a PKA-interacting protein (AKIP1) that binds to the amino terminus (residues 1-39) of the C subunit of PKA. The interaction was localized to the A helix (residues 14-39) of the C subunit and to the carboxyl terminus of AKIP1. AKIP1 thus defines the amino-terminal A helix of PKA as a protein interaction motif. In normal breast (Hs 578 Bst) and HeLa cells, AKIP1 is present in the nucleus as speckles. A nuclear localization signal (Arg-14 and Arg-15) was identified. Upon stimulation with forskolin, HeLa cells expressing AKIP1 accumulated higher levels of the endogenous C subunit in the nucleus. Deletion of the carboxyl terminus of AKIP1 or overexpression of residues 1-39 of the C subunit abolished nuclear localization of the activated endogenous C subunit. Thus, AKIP1 describes a PKA-interacting protein that can contribute to localization by a mechanism that is distinct from A-kinase anchoring proteins that interact with the regulatory subunits.