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4BBK

Structural and functional characterisation of the kindlin-1 pleckstrin homology domain

Summary for 4BBK
Entry DOI10.2210/pdb4bbk/pdb
DescriptorFERMITIN FAMILY HOMOLOG 1, GLYCEROL (3 entities in total)
Functional Keywordsph domain, cell adhesion
Biological sourceMUS MUSCULUS (HOUSE MOUSE)
Total number of polymer chains1
Total formula weight18961.03
Authors
Yates, L.A.,Lumb, C.N.,Brahme, N.N.,Zalyte, R.,Bird, L.E.,De Colibus, L.,Owens, R.J.,Calderwood, D.A.,Sansom, M.S.P.,Gilbert, R.J.C. (deposition date: 2012-09-25, release date: 2012-11-14, Last modification date: 2023-12-20)
Primary citationYates, L.A.,Lumb, C.N.,Brahme, N.N.,Zalyte, R.,Bird, L.E.,De Colibus, L.,Owens, R.J.,Calderwood, D.A.,Sansom, M.S.P.,Gilbert, R.J.C.
Structural and Functional Characterisation of the Kindlin-1 Pleckstrin Homology Domain
J.Biol.Chem., 287:43246-, 2012
Cited by
PubMed Abstract: Inside-out activation of integrins is mediated via the binding of talin and kindlin to integrin β-subunit cytoplasmic tails. The kindlin FERM domain is interrupted by a pleckstrin homology (PH) domain within its F2 subdomain. Here, we present data confirming the importance of the kindlin-1 PH domain for integrin activation and its x-ray crystal structure at a resolution of 2.1 Å revealing a C-terminal second α-helix integral to the domain but found only in the kindlin protein family. An isoform-specific salt bridge occludes the canonical phosphoinositide binding site, but molecular dynamics simulations display transient switching to an alternative open conformer. Molecular docking reveals that the opening of the pocket would enable potential ligands to bind within it. Although lipid overlay assays suggested the PH domain binds inositol monophosphates, surface plasmon resonance demonstrated weak affinities for inositol 3,4,5-triphosphate (Ins(3,4,5)P(3); K(D) ∼100 μM) and no monophosphate binding. Removing the salt bridge by site-directed mutagenesis increases the PH domain affinity for Ins(3,4,5)P(3) as measured by surface plasmon resonance and enables it to bind PtdIns(3,5)P(2) on a dot-blot. Structural comparison with other PH domains suggests that the phosphate binding pocket in the kindlin-1 PH domain is more occluded than in kindlins-2 and -3 due to its salt bridge. In addition, the apparent affinity for Ins(3,4,5)P(3) is affected by the presence of PO(4) ions in the buffer. We suggest the physiological ligand of the kindlin-1 PH domain is most likely not an inositol phosphate but another phosphorylated species.
PubMed: 23132860
DOI: 10.1074/JBC.M112.422089
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.1 Å)
Structure validation

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