Crosstide is a synthetic peptide substrate for Akt.1 It corresponds to the amino acid sequence of glycogen synthase kinase 3 (GSK3) that surrounds the serine residue phosphorylated by p90 ribosomal S6 kinase 1 (RSK1) or p70 ribosomal S6 kinase (p70S6K). Crosstide has been used in the study of Akt activity.1,2 It is also a substrate for serum/glucocorticoid-regulated kinase family member 3 (SGK3).3
1.Cross, D.A.E., Slessi, D.R., Cohen, P., et al.Inhibition of glycogen synthase kinase-3 by insulin mediated by protein kinase BNature378(6559)785-789(1995) 2.Tanti, J.-F., Grillo, S., Gremeaux, T., et al.Potential role of protein kinase B in glucose transporter 4 translocation in adipocytesEndocrinology138(5)2005-2010(1997) 3.Dai, F., Yu, L., He, H., et al.Human serum and glucocorticoid-inducible kinase-like kinase (SGKL) phosphorylates glycogen syntheses kinase 3 beta (GSK-3β) at serine-9 through direct interactionBiochem. Biophys. Res. Commun.293(4)1191-1196(2002)