古菌ESCRT系统研究进展

内体分拣转运复合体（ESCRT，endosomal sorting complex required for transport）曾被认为是真核生物特有的系统，涉及膜重塑、泛素化蛋白质分拣等重要细胞生命过程。近年的研究显示，TACK（包括Thaumarchaeota、Aigarchaeota、Crenarchaeota和Korarchaeota门）古菌超门中存在着一类与分泌膜囊泡、古菌病毒出胞以及细胞分裂过程等膜重塑过程相关的细胞分裂（Cdv，cell division）系统，该系统中的CdvB和CdvC是真核生物ESCRT-III和Vps4的同源蛋白，提示真核生物ESCRT系统可能起源自古菌。然而，由于TACK古菌中缺少真核生物ESCRT系统的其他关键成分，这一假设仍有争议。最近发现的阿斯加德（Asgard）古菌是一类被认为与真核生物最近缘的古菌，其基因组具有较完整的ESCRT相关蛋白的编码基因，提示真核生物的ESCRT很可能起源于阿斯加德古菌。本文首先简要介绍真核生物ESCRT系统的组成及生物学功能，然后分别总结TACK古菌的Cdv系统和阿斯加德古菌的ESCRT系统的研究进展，重点讨论它们的组成及生物学功能，为进一步了解古菌ESCRT系统与真核生物起源的关系提供参考。

Research progress on eukaryotic-like ESCRT in archaea

Endosomal sorting complex required for transport (ESCRT) system, once it was considered to be a unique functional system of eukaryotic cells, involving many important cell life processes, such as membrane remodeling and ubiquitinated protein cargo sorting. Recent studies show that Cdv (cell division) system in TACK (Thaumarchaeota, Aigarchaeota, Crenarchaeota, and Korarchaeota) archaeal superphylum, which related to the membrane remodeling processes, such as secretory membrane vesicles, archaea virus exocytosis, and cell division. The Cdv system subunits, CdvB and CdvC, are the homologous protein of eukaryotic ESCRT-III and Vps4, which recommends eukaryotic ESCRT-III may be originated from archaea. However, this hypothesis is in debatable because of Cdv lack of other key components of eukaryotic ESCRTs. Until recently, the members of Asgard archaea superphylum, which is considered to be the closest known prokaryotic relatives of eukaryotes, have been annotated relatively complete ESCRT-related proteins in their genomes. It is great interesting if the biological functions of ESCRT system in Asgard archaea are similar with eukaryotic ESCRT system, as it will provide strong evidence to support that eukaryotic ESCRT system may originate from archaea, thus supporting the two-domains theory. In this review, we first briefly introduce the composition and biological functions of eukaryotic ESCRT system, then summarize the composition and biological functions of archaea ESCRT system, especially focus on Sulfolobus and Asgard archaea, thus providing a foundation for understanding the relationship between archaeal ESCRT system and the origin of eukaryotes.