Staurosporine

Staurosporine, a microbial alkaloid with antifungal activity, has been shown to inhibit a variety of kinases including PKA (K_i=7.0 nM), PKG (K_i=8.5 nM), MYLK (MLCK, K_i=1.3 nM), PKC (K_i=0.7 nM), CaMK (IC₅₀=20 nM), CAMKII (K_i=20nM), tyrosine kinases (IC₅₀=70 nM) and phosphorylase kinase (IC₅₀=0.5 nM). Inhibition is via interaction with the ATP binding site. It induces association of purified PKC with inside-out vesicles from erythrocyte membranes and augments PMA-induced ornithine decarboxylase. Staurosporine activates a bcl-2-regulated apoptosis pathway. Further, there is evidence that it inhibits c-Src, Cdc2, Cdk2, Cdk4, Cdk5, cGKI, cyclin A, cyclin B, cyclin D, Fgr, GSK-3 beta, Lyn, p35, Pim-3, PKC alpha, Syk and Topo II.