Structure of Human NatA and Its Regulation by the Huntingtin Interacting Protein HYPK
Structure of Human NatA and Its Regulation by the Huntingtin Interacting Protein HYPK
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DOI：
10.1016/j.str.2018.04.003
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发表时间：
2018-07-03
期刊：
影响因子：
5.7
通讯作者：
Marmorstein, Ronen
中科院分区：
文献类型：
--
作者：
Gottlieb, Leah;Marmorstein, Ronen
共翻译N-末端蛋白乙酰化调节许多蛋白质功能，包括降解、折叠、蛋白质间相互作用和靶向。人NatA（hNatA）是后生动物中六种保守的N-末端乙酰转移酶之一，含有Naa 10催化亚基和Naa 15辅助亚基，与固有无序的亨廷顿酵母双杂交蛋白K（HYPK）结合。我们报告的晶体结构的hNatA和hNatA/HYPK，相关的生化和酶的分析。我们证明，hNatA含有独特的功能：一个稳定的肌醇六磷酸（IP 6）分子和一个后生动物特异性的Naa 15域，介导高亲和力HYPK结合。我们发现HYPK通过一个二分结构具有内在的hNatA特异性抑制活性：一个结合hNaa 15后生动物特异性区域的泛素相关结构域和一个扭曲hNaa 10活性位点的N-末端环螺旋区域。我们发现HYPK结合阻断了hNaa 50靶向hNatA，可能限制了体内Naa 50核糖体的定位。这些研究为后生动物NAT活性和HYPK调节N-末端乙酰化提供了模型。
Co-translational N-terminal protein acetylation regulates many protein functions including degradation, folding, interprotein interactions, and targeting. Human NatA (hNatA), one of six conserved metazoan N-terminal acetyltransferases, contains Naa10 catalytic and Naa15 auxiliary subunits, and associates with the intrinsically disordered Huntingtin yeast two-hybrid protein K (HYPK). We report on the crystal structures of hNatA and hNatA/HYPK, and associated biochemical and enzymatic analyses. We demonstrate that hNatA contains unique features: a stabilizing inositol hexaphosphate (IP6) molecule and a metazoan-specific Naa15 domain that mediates high-affinity HYPK binding. We find that HYPK harbors intrinsic hNatA-specific inhibitory activity through a bipartite structure: a ubiquitin-associated domain that binds a hNaa15 metazoan-specific region and an N-terminal loop-helix region that distorts the hNaa10 active site. We show that HYPK binding blocks hNaa50 targeting to hNatA, likely limiting Naa50 ribosome localization in vivo. These studies provide a model for metazoan NAT activity and HYPK regulation of N-terminal acetylation.