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Deciphering the dynamic regulation of phosphoinositide 3‐kinases downstream of G‐protein coupled receptors and receptor tyrosine kinases (1008.1)
Author(s) -
Burke John,
Vadas Oscar,
Perisic Olga,
Williams Roger L
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1008.1
Subject(s) - g protein coupled receptor , receptor tyrosine kinase , chemistry , p110α , microbiology and biotechnology , gene isoform , kinase , phosphoinositide 3 kinase , biochemistry , receptor , signal transduction , pi3k/akt/mtor pathway , biology , gene
>Class I phosphoinositide 3 kinases (PI3K) are activated downstream of G protein coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs), mediating a number of physiological, and pathophysiological processes including inflammation, and tumour growth. We have determined the molecular basis for the activation of PI3Ks downstream of GPCRs and RTKs by applying a synthesis of hydrogen deuterium exchange mass spectrometry (HDX‐MS), X‐ray crystallography and biochemical/cellular assays. HDX‐MS provides information on the conformation and solvent accessibility of protein amide hydrogens, and has allowed us to interrogate the structural dynamics of these protein complexes on a membrane surface. The class I PI3Ks are composed of four different catalytic isoforms (p110α, p110β, p110δ, and p110γ), and only the p110β and p110γ isoforms can be activated directly by Gβγ subunits derived from GPCRs. However, this interaction only occurs on a membrane surface. By biochemically reconstituting PI3K with Gβγ on a membrane surface and carrying out HDX‐MS experiments we were able to determine the molecular interface of both p110β and p110γ with Gβγ subunits. Intriguingly we find that membrane binding causes conformational changes at the Gβγ interface, revealing a key dynamic role for membrane binding in priming activation downstream of GPCRs. Mutations that disrupted the Gβγ interface prevented oncogenic transformation, revealing a key role of GPCR signalling in mediating oncogenic transformation through PI3Ks.