title: An in cellulo-derived structure of PAK4 in complex with its inhibitor Inka1.
abstract: PAK4 is a metazoan-specific kinase acting downstream of Cdc42. Here we describe the structure of human PAK4 in complex with Inka1, a potent endogenous kinase inhibitor. Using single mammalian cells containing crystals 50 μm in length, we have determined the in cellulo crystal structure at 2.95 Å resolution, which reveals the details of how the PAK4 catalytic domain binds cellular ATP and the Inka1 inhibitor. The crystal lattice consists only of PAK4-PAK4 contacts, which form a hexagonal array with channels of 80 Å in diameter that run the length of the crystal. The crystal accommodates a variety of other proteins when fused to the kinase inhibitor. Inka1-GFP was used to monitor the process crystal formation in living cells. Similar derivatives of Inka1 will allow us to study the effects of PAK4 inhibition in cells and model organisms, to allow better validation of therapeutic agents targeting PAK4.
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.
authors.forename: Yohendran
authors.identifier: http://orcid.org/0000-0001-7021-3042
authors.initials: Y
authors.lastname: Baskaran
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.|Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Khay C
authors.identifier: http://orcid.org/0000-0002-1846-6963
authors.initials: KC
authors.lastname: Ang
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.
authors.forename: Praju V
authors.initials: PV
authors.lastname: Anekal
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.
authors.forename: Wee L
authors.initials: WL
authors.lastname: Chan
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.|Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Grimes
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.|Institute of Medical Biology, A*STAR, Biopolis, Singapore 138648, Singapore.|Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Ed
authors.initials: E
authors.lastname: Manser
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Proteos Building, 61 Biopolis Drive, 8-15, Singapore 138673, Singapore.|Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robinson
mesh_terms: D000255:Adenosine Triphosphate; D000818:Animals; D019556:COS Cells; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D018613:Microscopy, Confocal; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054462:p21-Activated Kinases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D047908:Intracellular Signaling Peptides and Proteins; D054462:p21-Activated Kinases; C000607775:INKA1 protein, human; C116367:PAK4 protein, human