Shrimp plasma calcyphosine enhances hemocyte immune responses by promoting glycolysis

Calcyphosine, a highly conserved calcium-binding protein found in metazoans, has been recognized as a cell cycle regulator associated with poor cancer prognosis. However, its extracellular functions remain largely unknown. Here, we investigated its role as a plasma protein in the marine invertebrate Litopenaeus vannamei. This protein was primarily expressed in nerve and intestine, and its expression could be induced by lipopolysaccharide (LPS) treatment and accumulated on the surface of specific hemocytes. Differential transcriptomic analysis revealed its regulatory roles in glycolysis- and immunity-related pathways. Further assays indicated that recombinant calcyphosine could induce key glycolytic enzymes, including PCK2, Hex-t2, and TPI isoforms, reduce mitochondrial membrane potential, and increase lactate production at 8 h post-injection (hpi). Additionally, recombinant calcyphosine treatment stimulated immune effectors such as ALF, PEN2, Crustin1, and PPAF2, enhanced phagocytosis and increased hemocyte phagocytic rate and Caspase 3/7 activity at 8 hpi. These data suggest that calcyphosine likely functions as a general regulator of metabolism and immune responses in metazoan body fluids.