Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China.
Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian 116023, China.
Int J Mol Sci. 2024 Jul 25;25(15):8119. doi: 10.3390/ijms25158119.
The mammalian complement system constitutes a highly sophisticated body defense machinery. The evolutionary origin of the complement system can be traced to Coelenterata as the presence of the central component C3 and two activation proteases BF and MASP. In the present study, the main complement components were screened and analyzed from the genomes of different species in metazoan subphyla/phyla. C1q with classical domains can be traced to Annelida, and ficolin and MBL to Urochordata. C1r and C1s are only found in Chondrichthyes and even higher species, and MASP is traced to Coelenterata. In the evolutionary tree, C1r from Vertebrates is close to MASP1/2/3 from Deuterostomia and Coelenterata, and C1s from Vertebrates is close to MASP-like protease (MASPL) from Arthropoda, Mollusca, and Annelida. C2, BF, and DF can be traced to Mollusca, Coelenterata, and Porifera, respectively. There are no clear C2 and BF branches in the evolutionary tree. C3 can be traced to Coelenterata, and C4 and C5 are only in Chondrichthyes and even higher species. There are three clear C3, C4, and C5 branches in the evolutionary tree. C6-like (C6L) and C8 can be traced to Urochordata, and C7-like (C7L) can be traced to Cephalochordara. C6L, C7L, and C8 from Urochordata and Cephalochordara provide the structural conditions for the formation of Vertebrate MAC components. The findings unveil the evolutionary principles of the complement system and provide insight into its sophistication.
哺乳动物补体系统构成了高度复杂的机体防御机制。补体系统的进化起源可以追溯到腔肠动物，因为存在中心成分 C3 和两种激活蛋白酶 BF 和 MASP。在本研究中，从后生动物门亚门/门的不同物种的基因组中筛选和分析了主要的补体成分。具有经典结构域的 C1q 可以追溯到环节动物门，ficolin 和 MBL 可以追溯到尾索动物亚门。C1r 和 C1s 仅在软骨鱼类和更高等的物种中发现，而 MASP 可以追溯到腔肠动物。在进化树中，来自脊椎动物的 C1r 与后口动物和腔肠动物的 MASP1/2/3 接近，而来自脊椎动物的 C1s 与节肢动物、软体动物和环节动物的 MASPL 类似蛋白酶接近。C2、BF 和 DF 分别可以追溯到软体动物门、腔肠动物门和多孔动物门。进化树中没有明显的 C2 和 BF 分支。C3 可以追溯到腔肠动物门，而 C4 和 C5 仅在软骨鱼类和更高等的物种中发现。进化树中有三个明显的 C3、C4 和 C5 分支。来自尾索动物门和头索动物亚门的 C6 样（C6L）和 C8 可以追溯到尾索动物门，而 C7 样（C7L）可以追溯到头索动物亚门。来自尾索动物门和头索动物亚门的 C6L、C7L 和 C8 为脊椎动物 MAC 成分的形成提供了结构条件。这些发现揭示了补体系统的进化原则，并深入了解了其复杂性。
