Participation Of Apoptotic Caspase In Eriocheir Sinensis Innate Immune Response

In invertebrates, the cellular immune is incredibly efficient in innate immunity. Apoptosis, the last part of cellular defence, is important for eradicating pathogens and protecting the healthy cells. The present study focus on the Caspase.The Caspase-3-like gene was cloned from Eriocheir sinensis, and its properties were characterized to identify the biological implications of this caspase in apoptosis in crab. Its deduced full-length protein sequence consists of 482 amino acid residues, including the prodomain and the large and small subunits. Moreover, several residues known to be critical in the Caspase-3 catalytic center and binding pocket, as well as the active site pentapeptide motif Q220ACRG224, were identically present in the deduced EsCaspase-3-like protein. Subsequently, the recombinant EsCaspase-3-like (rEsCaspase-3-like) protein was expressed from Escherichia coli and obtained via affinity purification. Results of the in vitro enzymatic activity assays indicated that the rEsCaspase-3-like protein is capable of hydrolyzing the substrate Ac-DEVD-pNA, suggesting a functional role in physiology. EsCaspase-3-like gene transcripts were found to be widely distributed in all tissues as detected by quantitative RT-PCR, being especially abundant in hemocytes and comparatively rare in muscles. Furthermore, EsCaspase-3-like, at both the mRNA and protein levels, was demonstrated to participate in the apoptotic process after stimulation by different pathogen-associated molecular patterns (PAMPs) in hemocytes.In conclusion, our findings suggested that the EsCaspase-3-like protein functions as an effector caspase and contributes to immune responses against pathogens. This study has important meaning to expand the knowledge about molecular mechanism of invertebrate. Besides, the results would provide the theoretical basis for preventing diseases in valuable aquatic products.