CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266404, China.
Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China.
Genes (Basel). 2024 Apr 25;15(5):540. doi: 10.3390/genes15050540.
Caspase (CASP) is a protease family that plays a vital role in apoptosis, development, and immune response. Herein, we reported the identification and characterization of two CASPs, AjCASPX1 and AjCASPX2, from the sea cucumber , an important aquaculture species. AjCASPX1/2 share similar domain organizations with the vertebrate initiator caspases CASP2/9, including the CARD domain and the p20/p10 subunits with conserved functional motifs. However, compared with human CASP2/9, AjCASPX1/2 possess unique structural features in the linker region between p20 and p10. AjCASPX1, but not AjCASPX2, induced marked apoptosis of human cells by activating CASP3/7. The recombinant proteins of AjCASPX2 and the CARD domain of AjCASPX2 were able to bind to a wide range of bacteria, as well as bacterial cell wall components, and inhibit bacterial growth. AjCASPX1, when expressed in , was able to kill the host bacteria. Under normal conditions, AjCASPX1 and AjCASPX2 expressions were most abundant in sea cucumber muscle and coelomocytes, respectively. After bacterial infection, both AjCASPX1 and AjCASPX2 expressions were significantly upregulated in sea cucumber tissues and cells. Together, these results indicated that AjCASPX1 and AjCASPX2 were initiator caspases with antimicrobial activity and likely functioned in apoptosis and immune defense against pathogen infection.
半胱氨酸天冬氨酸蛋白酶（Caspase，CASP）是一个在细胞凋亡、发育和免疫反应中起关键作用的蛋白酶家族。本文报道了从海参中鉴定和表征的两种 CASP，AjCASPX1 和 AjCASPX2，海参是一种重要的水产养殖物种。AjCASPX1/2 与脊椎动物起始 Caspase CASP2/9 具有相似的结构域组织，包括 CARD 结构域和 p20/p10 亚基，具有保守的功能基序。然而，与人类 CASP2/9 相比，AjCASPX1/2 在 p20 和 p10 之间的连接区具有独特的结构特征。AjCASPX1 而非 AjCASPX2 通过激活 CASP3/7 诱导人细胞发生明显的凋亡。AjCASPX2 的重组蛋白和 AjCASPX2 的 CARD 结构域能够与多种细菌以及细菌细胞壁成分结合，并抑制细菌生长。AjCASPX1 在 中表达时能够杀死宿主细菌。在正常情况下，AjCASPX1 和 AjCASPX2 的表达在海参肌肉和体腔细胞中最为丰富。在细菌感染后，AjCASPX1 和 AjCASPX2 在海参组织和细胞中的表达均显著上调。总之，这些结果表明 AjCASPX1 和 AjCASPX2 是具有抗菌活性的起始 Caspase，可能在细胞凋亡和免疫防御方面发挥作用，以抵抗病原体感染。
