• Authors: Kjaer, S., Linch, M., Purkiss, A., Kostelecky, B., Knowles, P. P., Rosse, C., Riou, P., Soudy, C., Kaye, S., Patel, B., Soriano, E., Murray-Rust, J., Barton, C., Dillon, C., Roffey, J., Parker, P. J., McDonald, N. Q.
  • Year: 2013
  • Journal: Biochem J 451 329-42
  • Applications: in vitro / DNA / jetPEI
  • Cell type: HEK-293
    Description: Human embryonic kidney Fibroblast
    Known as: HEK293, 293


The aPKC [atypical PKC (protein kinase C)] isoforms iota and zeta play crucial roles in the formation and maintenance of cell polarity and represent attractive anti-oncogenic drug targets in Ras-dependent tumours. To date, few isoform-specific chemical biology tools are available to inhibit aPKC catalytic activity. In the present paper, we describe the identification and functional characterization of potent and selective thieno[2,3-d]pyrimidine-based chemical inhibitors of aPKCs. A crystal structure of human PKCiota kinase domain bound to a representative compound, CRT0066854, reveals the basis for potent and selective chemical inhibition. Furthermore, CRT0066854 displaces a crucial Asn-Phe-Asp motif that is part of the adenosine-binding pocket and engages an acidic patch used by arginine-rich PKC substrates. We show that CRT0066854 inhibits the LLGL2 (lethal giant larvae 2) phosphorylation in cell lines and exhibits phenotypic effects in a range of cell-based assays. We conclude that this compound can be used as a chemical tool to modulate aPKC activity in vitro and in vivo and may guide the search for further aPKC-selective inhibitors.