Substrate and inhibitor specificity of the type II p21-activated kinase, PAK6.

Publication Type:

Journal Article


PLoS One, Volume 8, Issue 10, p.e77818 (2013)


Amino Acid Sequence, Catalytic Domain, Crystallization, Crystallography, X-Ray, HEK293 Cells, Humans, Indoles, Models, Molecular, Molecular Sequence Data, p21-Activated Kinases, Peptide Fragments, Phosphorylation, Protein Conformation, Pyrazoles, Pyrroles, Sequence Homology, Amino Acid, Signal Transduction, Substrate Specificity, Sunitinib


<p>The p21-activated kinases (PAKs) are important effectors of Rho-family small GTPases. The PAK family consists of two groups, type I and type II, which have different modes of regulation and signaling. PAK6, a type II PAK, influences behavior and locomotor function in mice and has an ascribed role in androgen receptor signaling. Here we show that PAK6 has a peptide substrate specificity very similar to the other type II PAKs, PAK4 and PAK5 (PAK7). We find that PAK6 catalytic activity is inhibited by a peptide corresponding to its N-terminal pseudosubstrate. Introduction of a melanoma-associated mutation, P52L, into this peptide reduces pseudosubstrate autoinhibition of PAK6, and increases phosphorylation of its substrate PACSIN1 (Syndapin I) in cells. Finally we determine two co-crystal structures of PAK6 catalytic domain in complex with ATP-competitive inhibitors. We determined the 1.4 Å co-crystal structure of PAK6 with the type II PAK inhibitor PF-3758309, and the 1.95 Å co-crystal structure of PAK6 with sunitinib. These findings provide new insights into the structure-function relationships of PAK6 and may facilitate development of PAK6 targeted therapies.</p>