K-252a is a staurosporine analog isolated from Nocardiopsis sp. soil fungi. K-252a inhibits protein kinase (IC50: 470 nM, 140 nM, 270 nM, and 1.7 nM for PKC, PKA, Ca2+ calmodulin-dependent kinase type II, and phosphorylase kinase, respectively).
KT5926 is an effective and selective inhibitor of myosin light chain kinase. KT5926 is an analogue of K-252a, which blocks all responses to NGF. KT5926 selectively inhibits nerve growth factor-dependent neurite elongation.