Toxin that acts as an agonist on melanocortin receptors (MC1R, MC3R, MC5R, MC5R). After binding to MC1R, the peptide activates the hMC1R/Gs pathway, but after binding to MC4R, it is not able to activate or antagonize the MC4R/Gs pathway. Inhibits melanocyte stimulating hormone (MSH)-binding to human receptors (Ki=1.8 uM to MC1R, Ki=19.8 uM to MC3R, Ki=7.1 uM to MC4R, Ki=10.0 uM to MC5R). This toxin is structurally unrelated to the natural agonists. Toxin that acts as an agonist on melanocortin receptors (MC1R, MC3R, MC5R, MC5R). After binding to MC1R, the peptide activates the hMC1R/Gs pathway, but after binding to MC4R, it is not able to activate or antagonize the MC4R/Gs pathway. Inhibits melanocyte stimulating hormone (MSH)-binding to human receptors (Ki=2.9 uM to MC1R, Ki=3.9 uM to MC3R, Ki=2.6 uM to MC4R, Ki=2.2 uM to MC5R). This toxin is structurally unrelated to the natural agonists. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Does not show activity when tested at 100 uM on mammalian sodium channels (Nav1.1, Nav1.2, Nav1.3, Nav1.4, Nav1.5, Nav1.6, Nav1.7, and Nav1.8), potassium channels (Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv1.6, Kv2.1, Kv3.1, Kv4.3, Kv7.1, Kv7.3, Kv10.1, Kv11.1(hERG), GIRK1), a calcium channel (Cav3.3), and nicotinic acetylcholine receceptors alpha1-beta-1-gamma-delta and nAChR alpha-7. The letter 'N' in the name stands for the Greek letter 'nu' that has been chosen as the activity descriptor for melanocortin receptor modulators. Since it is impossible to search for Greek letters in databases, the UniProt policy is to write all Greek letters as their full names (i.e. alpha, beta, etc.).