Vitellogenin and vitellogenin receptor in crustaceans: Macromolecular design rules linking yolk deposition, oocyte...

Vitellogenin (Vg) and the vitellogenin receptor (VgR) are usually discussed as endocrine readouts of ovarian maturation. Here they are treated as a coupled macromolecular system: a high-mass lipid/glyco-protein that must remain stable in hemolymph and a modular endocytic receptor that governs selective uptake, intracellular routing, and storage conversion. This perspective brings several underused mechanistic layers into focus. First, Vg performance is likely encoded by proteoforms created by glycosylation, proteolytic processing, and cargo loading, as shown by site-specific high-mannose glycans in crayfish Vg. Second, VgR functions as a kinetic throughput valve whose binding and recycling properties can become rate-limiting for yolk deposition, supported by receptor biochemistry in mud crab and functional silencing in shrimp. Third, immune functions and reproduction are directly coupled which Vg not only binds microbes via defined domains but also provides systemic antiviral and antioxidant defense, while ovarian VgR expression can modulate systemic immunity by regulating hemolymph Vg accumulation. Finally, recent evidence indicates that VgR-mediated uptake is a stress-buffering mechanism that protects vitellogenic oocyte formation under broader environmental challenges, including thermal, salinity, and heavy metal stress. We synthesize these findings into testable design rules and propose a practical toolkit such as glycoproteomics, lipidomics, binding biophysics, and structure-guided functional assays to move the field from transcript-level descriptions to predictive, intervention-ready mechanisms for elite aquaculture breeding and farm management.