Molecular cloning and functional characterization of sarco/endoplasmic reticulum Ca2+-ATPase from Chinese mitten crab (Eriocheir sinensis)

Ca2+ plays an important role in signal transduction and regulates various physiological functions of cells. The active transport of Ca2+ from the cytosol to the lumen of the sarcoplasmic or endoplasmic reticulum occurs via sarco/endoplasmic reticulum Ca2+-ATPases (SERCA). However, the function of this protein during moulting cycles remains unclear in Chinese mitten crab (Eriocheir sinensis). In this study, we cloned a cDNA encoding a putative SERCA protein from the Y-organs (moulting glands) in E. sinensis. The cloned Es-SERCA cDNA (4552 bp) included an open reading frame of 3003 bp encoding a 1000-residue protein with a predicted molecular mass of 109.60 kDa. The predicted Es-SERCA protein was clustered with those from other arthropods in phylogenetic analysis. Further, qPCR revealed that Es-SERCA was widely expressed in in all tested tissues with the highest expression in the muscle, followed by the eyestalks, intestines, hepatopancreas, Y-organs and gills. The stage-specific fluctuations among different tissues indicated a functional role of SERCA in calcium homeostasis. The relative mRNA level of the Es-SERCA in Y-organs during the moulting cycle was similar to the level trend of ecdysteroid concentration in haemolymph, indicating that Ca2+ signalling stimulated ecdysteroid synthesis in Y-organs. Altogether, our study provides a reference for further research on the molecular mechanisms of the moulting in E. sinensis.

Automated summary

This study cloned a cDNA encoding a putative SERCA protein from the Y-organs of E. sinensis. The Es-SERCA protein was widely expressed in various tissues, with the highest expression in the muscle. The study also revealed the functional role of SERCA in calcium homeostasis and its involvement in ecdysteroid synthesis during the moulting cycle.