Longdaysin is a CK1α, CK1δ, and extracellular signal-regulated kinase 2 (ERK2) inhibitor with IC50s of 5.6 µM, 8.8 µM, and 52 µM, respectively[1][2]. CKIα|5.6 μM (IC50)|CKIδ|8.8 μM (IC50)|ERK2|52 μM (IC50)
[1]. 1.Griffett K, et al. The mammalian clock and chronopharmacology. Bioorganic & Medicinal Chemistry Letters, 2013, 23(7):1929-1934.. [2]. Hirota T, et al. High-throughput chemical screen identifies a novel potent modulator of cellular circadian rhythms and reveals CKIα as a clock regulatory kinase. PLoS Biol. 2010 Dec 14;8(12):e1000559.