1w1h

File:1w1h.gif

spinqualitylabelsall models 1w1h, resolution 1.45Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THE PDK1 PLECKSTRIN HOMOLOGY (PH) DOMAIN

OverviewOverview

3-phosphoinositide-dependent protein kinase-1 (PDK1) phosphorylates and, activates many kinases belonging to the AGC subfamily. PDK1 possesses a, C-terminal pleckstrin homology (PH) domain that interacts with, PtdIns(3,4,5)P3/PtdIns(3,4)P2 and with lower affinity to PtdIns(4,5)P2. We, describe the crystal structure of the PDK1 PH domain, in the absence and, presence of PtdIns(3,4,5)P3 and Ins(1,3,4,5)P4. The structures reveal a, 'budded' PH domain fold, possessing an N-terminal extension forming an, integral part of the overall fold, and display an unusually spacious, ligand-binding site. Mutagenesis and lipid-binding studies were used to, define the contribution of residues involved in phosphoinositide binding., Using a novel quantitative binding assay, we found that Ins(1,3,4,5,6)P5, and InsP6, which are present at micromolar levels in the cytosol, interact, with full-length PDK1 with nanomolar affinities. Utilising the isolated, PDK1 PH domain, which has reduced affinity for Ins(1,3,4,5,6)P5/InsP6, we, perform localisation studies that suggest that these inositol phosphates, serve to anchor a portion of cellular PDK1 in the cytosol, where it could, activate its substrates such as p70 S6-kinase and p90 ribosomal S6 kinase, that do not interact with phosphoinositides.

About this StructureAbout this Structure

1W1H is a Single protein structure of sequence from Homo sapiens with SO4 and GOL as ligands. Active as Transferred entry: 2.7.11.1, with EC number 2.7.1.37 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

ReferenceReference

Structural insights into the regulation of PDK1 by phosphoinositides and inositol phosphates., Komander D, Fairservice A, Deak M, Kular GS, Prescott AR, Peter Downes C, Safrany ST, Alessi DR, van Aalten DM, EMBO J. 2004 Oct 13;23(20):3918-28. Epub 2004 Sep 30. PMID:15457207

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