The molecular characterization of Rab11 and its immune roles in red swamp crayfish ( Procambarus clarkii )

The Rab proteins primarily regulate vesicular transport between membrane -bound organelles and are important for innate immune. However, there is currently a lack of studies on crustaceans regarding Rab proteins, particularly core Rabs. We identified a Rab11 gene from Procambarus clarkii ( PcRab11 ) and evaluated its potential involvement in immune response. The results showed PcRab11 was 1789 bp long, with an open reading frame of 645 bp encoding 211 amino acids and an estimated molecular weight of 23.8 kDa. Sequence analysis revealed its remarkable evolutionary conservation. The PcRab11 was widely expressed in various tissues, with highest levels in hepatopancreas, and localized within the cell cytoplasm. Upon infection with white spot syndrome virus (WSSV) or Aeromonas veronii , the expression of PcRab11 in immune organs was significantly induced. Furthermore, silencing PcRab11 reduced phagocytosis-related genes expression and haemocytes' phagocytic activity to FITC-labeled A. veronii , as well as decreased mortality and death time in WSSV or A. veronii infected P. clarkii . Additionally, the potential protein interaction between PcRab11 and 14-3-3 epsilon was identified in haemocytes. Overall, our findings provided evidence for the involvement of Rab11 in P. clarkii ' s immune response, establishing a foundation to explore the immune role of core Rab proteins in crustaceans' innate immune system.