Broad distribution, high diversity and ancient origin of the ApeC-containing proteins
Broad distribution, high diversity and ancient origin of the ApeC-containing proteins
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含 ApeC 的蛋白质分布广泛、多样性高且起源古老
DOI：
10.1016/j.ympev.2020.107009
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发表时间：
2021-02-01
影响因子：
4.1
通讯作者：
Huang, Shengfeng
中科院分区：
文献类型：
--
作者：
Li, Yuhui;Li, Jin;Huang, Shengfeng
APEC是一个新的蛋白质结构域，功能未知，但早期的研究表明，一些APEC蛋白(ACPs)与碳水化合物结合，在发育和免疫中发挥作用。本文调查了后生动物中ACPs的分类分布、序列多样性和起源。大多数ACPs存在于水生或潮湿环境中的无脊椎动物中，包括线虫、软体动物、棘皮动物、头藻、扁虫、水熊、线虫和环节动物。然而，除了节肢动物外，脊椎动物和大多数节肢动物(如昆虫和甲壳类)中都没有ACPs。ACP明显经历了快速的更替和多样化，因此在(亚)门之间找不到同源基因。APEC既可以作为独立的域名发挥作用，也可以作为合作伙伴的域名发挥作用。已经发现它在不同的ACP中与十多个不同的结构域类型配对。伙伴结构域与免疫、细胞外基质、蛋白质-蛋白质和蛋白质-碳水化合物相互作用有关。值得注意的是，分类分布最广的结构域对是MACPF/穿孔素-APEC，它代表了一组经典的ACP，称为apexins。亚太经合组织还经常与自己配对，形成不同门类的双APEC模块。值得注意的是，在寄生虫中，70%的ACP中存在双重APEC，它们都是从共同的祖先那里遗传来的。MACPF-APEC和Dual-APEC的广泛分布表明它们具有保守而未知的功能。我们还在细菌中发现了远距离的APEC同源物，从而将APEC的起源追溯到原核生物。我们的发现表明，APEC具有古老的起源，能够单独或在复杂的结构域结构中发挥作用，尽管它不像免疫球蛋白结构域和C型凝集素结构域那样普遍。这项工作为进一步研究这一新型结构域的功能奠定了基础。
Apextrin C-terminal (ApeC) is a novel protein domain with unknown functions, although early studies suggest that some ApeC-containing proteins (ACPs) bind to carbohydrates and have a role in development and immunity. Here we investigated the taxonomic distribution, sequence diversification and origin of ACPs in Metazoa.Most ACPs are present in invertebrates from aquatic or moist environments, including cnidarians, mollusks, echinoderms, cephalochordates, flatworms, water bears, nematodes and annelids. However, ACPs are absent in vertebrates and in most arthropod lineages (e.g. insects and crustaceans) except arachnids. ACPs apparently undergo rapid turnover and diversification, hence no orthologs could be found between (sub)phyla. ApeC can function either as a standalone domain or as a partner domain. It has been found to pair up with over ten different domain types in different ACPs. The partner domains are related to immunity, extracellular matrix, protein-protein and protein-carbohydrate interactions. Notably, the domain pair with the widest taxonomic distribution is MACPF/perforin-ApeC, which represent a classic group of ACPs called apextrins. ApeC also frequently pairs up with itself to form dual-ApeC modules in different phyla. Notably, in parasite flatworms, dual-ApeCs are present in 70% of ACPs and all inherited from a common ancestor. The broad distribution of MACPF-ApeC and dual-ApeC suggest their conserved yet unknown functions. We also discovered distant ApeC homologs in bacteria, hence tracing the origin of ApeC back to prokaryotes.Our findings show that ApeC has an ancient origin and is able to function alone or in complex domain architectures, though it is less prevalent than other versatile domains such as immunoglobulin domains and C-type lectin domains. This work provides a foundation for further functional study of this novel domain type.