APJ Protein-VLP, Human (HEK293)

APJ is a G protein-coupled receptor that binds peptide hormones apelin (APLN) and apelin receptor early endogenous ligand (APELA/ELA), playing a central role in regulating normal cardiovascular function and fluid homeostasis. As an apelin receptor, it activates both the G(i) protein pathway (inhibiting adenylate cyclase activity) and the beta-arrestin pathway (promoting receptor internalization). APLNR/APJ also functions as a mechanoreceptor, activated by pathological stimuli in a G-protein-independent manner to induce beta-arrestin signaling, thereby triggering cardiac hypertrophy, though apelin ligand presence blunts this pathological induction. During early development, it acts as an APELA receptor in gastrulation, blood vessel formation, and heart morphogenesis (by similar). It may promote angioblast migration toward the embryonic midline (future vessel formation site) (by similar) and drive sinus venosus (SV)-derived endothelial cell migration into the developing heart to support coronary vessel development (by similar). In adults, it further regulates blood vessel formation, blood pressure, heart contractility, and heart failure.