2. Academic Validation
  3. An in cellulo-derived structure of PAK4 in complex with its inhibitor Inka1

An in cellulo-derived structure of PAK4 in complex with its inhibitor Inka1

  • Nat Commun. 2015 Nov 26;6:8681. doi: 10.1038/ncomms9681.
Yohendran Baskaran 1,  Khay C Ang 1 2,  Praju V Anekal 1,  Wee L Chan 1,  Jonathan M Grimes 3 4,  Ed Manser 1 5 6,  Robert C Robinson 1 2
Affiliations

Affiliations

  • 1 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.
  • 2 Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
  • 3 Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
  • 4 Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
  • 5 Institute of Medical Biology, A*STAR, Biopolis, Singapore 138648, Singapore.
  • 6 Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
PMID: 26607847 DOI: 10.1038/ncomms9681
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.

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