Evolutionary and cellular analysis of the 'dark' pseudokinase PSKH2.
Evolutionary and cellular analysis of the 'dark' pseudokinase PSKH2.
复制标题
DOI：
10.1042/bcj20220474
复制
发表时间：
2023-01-31
期刊：
影响因子：
--
通讯作者：
中科院分区：
文献类型：
--
作者：
假激酶，如此命名是因为它们缺乏一个或多个定义其催化活性亲属的保守的典型氨基酸，在原核生物和真核生物中已经进化出多种生物学功能。人PSKH 2与典型激酶PSKH 1密切相关，PSKH 1定位于蛋白激酶的CAMK家族。灵长类以假激酶的形式编码PSKH 2，由于不变的催化性Asp残基的丢失，其被预测为无催化活性。尽管脊椎动物PSKH 2蛋白的生物学作用仍不清楚，但我们先前鉴定了PSKH 2中的物种水平适应，这些适应导致脊椎动物基因组中出现激酶或假激酶变体以及典型的PSKH 1蛋白。在本文中，我们证实，如预测的那样，PSKH 2缺乏可检测的蛋白磷酸转移酶活性，并利用结构信息学，生物化学和细胞蛋白质组学开始，以确定脊椎动物PSKH 2的直系同源物。基于AlphaFold 2的结构分析预测了PSKH 2 N-和C-区域的功能作用，这些区域位于假激酶结构域核心的侧翼，并且细胞截短分析证实了含有保守的肉豆蔻酰化位点的N-末端结构域是稳定的人PSKH 2表达和定位到含有线粒体蛋白的富含膜的亚细胞部分所必需的。使用质谱为基础的蛋白质组学，我们证实，人PSKH 2是细胞线粒体蛋白质网络的一部分，其表达是通过客户端的HSP 90/Cdc 37分子伴侣系统内的状态进行调节。HSP 90的相互作用是通过结合PSKH 2的C-末端尾部介导的，这使我们预测，该区域可能作为一个顺式和反式调节元件，驱动输出连接到PSKH 2假激酶结构域，这是重要的功能信号。
Pseudokinases, so named because they lack one or more conserved canonical amino acids that define their catalytically active relatives, have evolved a variety of biological functions in both prokaryotic and eukaryotic organisms. Human PSKH2 is closely related to the canonical kinase PSKH1, which maps to the CAMK family of protein kinases. Primates encode PSKH2 in the form of a pseudokinase, which is predicted to be catalytically inactive due to loss of the invariant catalytic Asp residue. Although the biological role(s) of vertebrate PSKH2 proteins remains unclear, we previously identified species-level adaptions in PSKH2 that have led to the appearance of kinase or pseudokinase variants in vertebrate genomes alongside a canonical PSKH1 paralog. In this paper we confirm that, as predicted, PSKH2 lacks detectable protein phosphotransferase activity, and exploit structural informatics, biochemistry and cellular proteomics to begin to characterise vertebrate PSKH2 orthologues. AlphaFold 2-based structural analysis predicts functional roles for both the PSKH2 N- and C-regions that flank the pseudokinase domain core, and cellular truncation analysis confirms that the N-terminal domain, which contains a conserved myristoylation site, is required for both stable human PSKH2 expression and localisation to a membrane-rich subcellular fraction containing mitochondrial proteins. Using mass spectrometry-based proteomics, we confirm that human PSKH2 is part of a cellular mitochondrial protein network, and that its expression is regulated through client-status within the HSP90/Cdc37 molecular chaperone system. HSP90 interactions are mediated through binding to the PSKH2 C-terminal tail, leading us to predict that this region might act as both a cis and trans regulatory element, driving outputs linked to the PSKH2 pseudokinase domain that are important for functional signalling.
影响因子：
1.4
作者：
Maeda Y;Fukushima K;Hirai M;Kariya S;Smith RJ;Nishizaki K
通讯作者：
Nishizaki K