The N-terminal region of ABC50 interacts with eukaryotic initiation factor eIF2 and is a target for regulatory phosphorylation by CK2
The N-terminal region of ABC50 interacts with eukaryotic initiation factor eIF2 and is a target for regulatory phosphorylation by CK2
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DOI：
10.1042/bj20070811
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发表时间：
2008-01-01
影响因子：
4.1
通讯作者：
Proud, Christopher G.
中科院分区：
文献类型：
--
作者：
Paytubi, Sonia;Morrice, Nicholas A.;Proud, Christopher G.
ABC 50是一种ABC（ATP结合盒）蛋白，与大多数ABC蛋白不同，它缺乏跨膜结构域。ABC 50与eIF 2（真核起始因子2）相互作用，eIF 2是一种在翻译起始及其控制以及核糖体调节中起关键作用的蛋白质。在这里，我们建立了ABC 50与eIF 2的相互作用涉及ABC 50的N-末端结构域中的特征，ABC 50的区域与其他ABC蛋白最显着不同。该区域与eIF 2的其他伴侣的eIF 2结合结构域也没有明显的相似性。相反，ABC 50的N端不能单独与核糖体结合，但它可以与其中一个核苷酸结合结构域结合。我们证明，ABC 50是一个磷蛋白，并在两个网站的CK 2磷酸化。这些位点，Ser-109和Ser-140，位于ABC 50的N-末端部分，但不是ABC 50与eIF 2结合所必需的。ABC 50的突变体的表达，其中两个位点都突变为丙氨酸显着降低了协会的eIF 2与80 S核糖体和多核糖体组分。
ABC50 is an ABC (ATP-binding cassette) protein which, unlike most ABC proteins, lacks membrane-spanning domains. ABC50 interacts with eIF2 (eukaryotic initiation factor 2), a protein that plays a key role in translation initiation and in its control, and in regulation of ribosomes. Here, we establish that the interaction of ABC50 with eIF2 involves features in the N-terminal domain of ABC50, the region of ABC50 that differs most markedly from other ABC proteins. This region also shows no apparent similarity to the eIF2-binding domains of other partners of eIF2. In contrast, the N-terminus of ABC50 cannot bind to ribosomes by itself, but it can in conjunction with one of the nucleotide-binding domains. We demonstrate that ABC50 is a phosphoprotein and is phosphorylated at two sites by CK2. These sites, Ser-109 and Ser-140, lie in the N-terminal part of ABC50 but are not required for the binding of ABC50 to eIF2. Expression of a mutant of ABC50 in which both sites are mutated to alanine markedly decreased the association of eIF2 with 80S ribosomal and polysomal fractions.