Adenosine-binding motif mimicry and cellular effects of a thieno[2,3-d]pyrimidine-based chemical inhibitor of atypical protein kinase C isoenzymes

• Published in: Biochemical journal Vol. 451; no. 2; p. 329
• Main Authors: Kjær, Svend, Linch, Mark, Purkiss, Andrew, Kostelecky, Brenda, Knowles, Phillip P, Rosse, Carine, Riou, Philippe, Soudy, Christelle, Kaye, Sarah, Patel, Bhavisha, Soriano, Erika, Murray-Rust, Judith, Barton, Caroline, Dillon, Christian, Roffey, Jon, Parker, Peter J, McDonald, Neil Q
• Format: Journal Article
• Language: English
• Published: England 15.04.2013
• Subjects: Adenosine - metabolism; Adenosine Triphosphate - chemistry; Adenosine Triphosphate - metabolism; Amino Acid Sequence; Animals; Binding Sites; Cell Line; Cell Movement - drug effects; Cell Survival - drug effects; Crystallography, X-Ray; Cytoskeletal Proteins - metabolism; Dogs; Drug Evaluation, Preclinical - methods; High-Throughput Screening Assays; Humans; Inhibitory Concentration 50; Isoenzymes - antagonists & inhibitors; Molecular Mimicry; Molecular Sequence Data; Phosphorylation; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - chemistry; Protein Kinase C - metabolism; Protein Kinase Inhibitors - chemical synthesis; Protein Kinase Inhibitors - chemistry; Protein Kinase Inhibitors - metabolism; Protein Kinase Inhibitors - pharmacology; Pyrimidines - chemistry; Pyrimidines - pharmacology; Thiophenes - chemistry; Thiophenes - pharmacology
• ISSN: 1470-8728
• DOI: 10.1042/bj20121871

The aPKC [atypical PKC (protein kinase C)] isoforms ι and ζ 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 PKCι 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.