A potent and highly specific cell-permeable protein kinase C (PKC) inhibitor . The inhibition of PKC is light-dependent. Also inhibits PKA, PKG, DAG kinase, phospholipase D1 and D2, myosin light chain kinase and c-Src . Anticancer compound. Inhibits cell proliferation and strongly induces apoptosis in vitro. Shown to directly and potently block L-type calcium channels. Calphostin C specifically inhibits contraction-stimulated glucose transport but not insulin-stimulated glucose transport in skeletal muscle. Also Wnt/β-catenin/lef-1 signaling inhibitor.