TLQP 21 is a peptide named for its four N-terminal amino acids and length, which is derived from the 617 amino acid VGF precursor by proteolytic processing. The target for TLQP 21 is the C3a receptor-1 (C3aR1), a G-protein coupled receptor that is activated by the complement activation product C3a, itself considered a component of innate immunity. TLQP 21 plays a role in the central and peripheral nervous system to regulate feeding, reproductive and circadian behaviours and has a role in neuropathic pain and peripheral adiposity.
