Genome-wide identification of ApeC domain-containing protein and revealing the function of ChACP-1.10 in oyster mucosal immunity.

The Apextrin C-terminal (ApeC) domain-containing protein (ACP), a poorly studied gene family that is found exclusively in invertebrates, plays critical roles in mucosal immunity. However, the evolution and immunological mechanisms of ACP in oysters remain elusive. In this study, a total 148 ACP genes were identified in six oyster species genomes and were classified into five subgroups based on their domain architectures and phylogenetic analysis.

ChNLRC4, a cytoplasmic pattern recognition receptor, activates the pyroptosis signaling pathway in Mollusca.

NLR inflammasomes recognize pathogen-associated molecular patterns (PAMPs), triggering Caspase-1 activation and leading to gasdermin D (GSDMD)-mediated pyroptosis, a crucial immune response in mammals. The functional GSDME-mediated pyroptosis has been reported in invertebrates, yet the existence of an NLR-Caspase-GSDME axis mediating pyroptosis signaling cascades remains unclear. In this study, we reported an NLRC4 homolog named ChNLRC4, a pattern recognition receptor from the oyster Crassostrea hongkongensis that is able to bind to LPS and Lys-type PGN through its LRR domain.

ChRIPK1 caused necroptosis signaling pathway deficiency in Crassostrea hongkongensis.

RIPK1/TAK1 are important for programmed cell death, including liver death, necroptosis and apoptosis. However, there have been few published reports on the functions of RIPK1/TAK1 in invertebrates. In this study, full-length ChRIPK1 and ChTAK1 were cloned from C.