K252a

K252a is a staurosporine analog isolated from Nocardiopsis sp. soil fungi that inhibits protein kinase (PK) C, PKA, Ca2+/calmodulin-dependent kinase type II, and phosphorylase kinase with IC50 values of 470, 140, 270, and 1.7 nM, respectively.{21294,17276} Because it inhibits neurotrophin receptor tyrosine kinases, K252a at 100-500 nM has been used to suppress trophoblast proliferation and increase apoptosis associated with the disruption of mitochondrial functions in cultured choriocarcinoma cells.{21290} Recently, K252a has been shown to inhibit PRK1 (IC50 = 3.2 nM in vitro), a PKC-related kinase that phosphorylates histone H3 at threonine 11 and is involved in androgen-dependent gene expression.{21798}