Discovery of a selective inhibitor of oncogenic B-Raf kinase with potent antimelanoma activity.

BRAF(V600E) is the most frequent oncogenic protein kinase mutation known. Furthermore, inhibitors targeting "active" protein kinases have demonstrated significant utility in the therapeutic repertoire against cancer. Therefore, we pursued the development of specific kinase inhibitors targeting B-Raf, and the V600E allele in particular.

Phosphodiesterase-4 as a potential drug target.

Phosphodiesterase-4 (PDE4) is the predominant enzyme in some specific cell types that is responsible for the degradation of the second messenger, cAMP. Consequently, PDE4 plays a crucial role in cell signalling and, as such, it has been the target of clinical drug development of various indications, ranging from anti-inflammation to memory enhancement. In this review, the fundamental biological role of PDE4 in intracellular signalling, its tissue distribution and regulation are described.

A family of phosphodiesterase inhibitors discovered by cocrystallography and scaffold-based drug design.

Cyclic nucleotide phosphodiesterases (PDEs) comprise a large family of enzymes that regulate a variety of cellular processes. We describe a family of potent PDE4 inhibitors discovered using an efficient method for scaffold-based drug design. This method involves an iterative approach starting with low-affinity screening of compounds followed by high-throughput cocrystallography to reveal the molecular basis underlying the activity of the newly identified compounds.

Structural basis for the activity of drugs that inhibit phosphodiesterases.

Phosphodiesterases (PDEs) comprise a large family of enzymes that catalyze the hydrolysis of cAMP or cGMP and are implicated in various diseases. We describe the high-resolution crystal structures of the catalytic domains of PDE4B, PDE4D, and PDE5A with ten different inhibitors, including the drug candidates cilomilast and roflumilast, for respiratory diseases. These cocrystal structures reveal a common scheme of inhibitor binding to the PDEs: (i) a hydrophobic clamp formed by highly conserved hydrophobic residues that sandwich the inhibitor in the active site; (ii) hydrogen bonding to an invariant glutamine that controls the orientation of inhibitor binding.

A glutamine switch mechanism for nucleotide selectivity by phosphodiesterases.

Phosphodiesterases (PDEs) comprise a family of enzymes that modulate the immune response, inflammation, and memory, among many other functions. There are three types of PDEs: cAMP-specific, cGMP-specific, and dual-specific. Here we describe the mechanism of nucleotide selectivity on the basis of high-resolution co-crystal structures of the cAMP-specific PDE4B and PDE4D with AMP, the cGMP-specific PDE5A with GMP, and the apo-structure of the dual-specific PDE1B.