RP-220 is a 20 amino acid renalase peptide(aa 220–239: CIRFVSIDNKKRNIESSEIG), which is conserved in all known isoforms but is devoid of any detectable oxidase activity, was equally effective as intact renalase protein at protecting HK-2 cells and WT mice against toxic and ischemic injury. RP-220 and recombinant renalase rapidly activated protein kinase B (AKT), extracellular signal-regulated kinase (ERK), and mitogen activated protein kinase (p38) mitogen activated protein kinases, suggesting that RP-220 is the region of the renalase protein critical for interaction with its cognate receptor. RP-220 also has a pro-survival role for RP-220 following alkaline insult to corneal epithelial cells.
Wang L, Velazquez H, Chang J, Safirstein R, Desir GV. Identification of a receptor for extracellular renalase. PLoS One. 2015;10(4):e0122932. Published 2015 Apr 23. doi:10.1371/journal.pone.0122932
Potts L, Phillips C, Hwang M, Fulcher S, Choi H. Rescue of human corneal epithelial cells after alkaline insult using renalase derived peptide, RP-220. Int J Ophthalmol. 2019;12(11):1667u20131673. Published 2019 Nov 18. doi:10.18240/ijo.2019.11.01