title: Substrate and inhibitor specificity of the type II p21-activated kinase, PAK6.
abstract: 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.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-biosciences, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China ; Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: Jia
authors.initials: J
authors.lastname: Gao
authors.forename: Byung Hak
authors.initials: BH
authors.lastname: Ha
authors.forename: Hua Jane
authors.initials: HJ
authors.lastname: Lou
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Morse
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: David A
authors.initials: DA
authors.lastname: Calderwood
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Turk
authors.forename: Titus J
authors.initials: TJ
authors.lastname: Boggon
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003460:Crystallization; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D007211:Indoles / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011487:Protein Conformation; D011720:Pyrazoles / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013379:Substrate Specificity; D000077210:Sunitinib; D054462:p21-Activated Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D007211:Indoles; C550923:PF 3758309; D010446:Peptide Fragments; D011720:Pyrazoles; D011758:Pyrroles; C429007:PAK6 protein, human; D054462:p21-Activated Kinases; D000077210:Sunitinib