2014
Miller, Michelle S; Schmidt-Kittler, Oleg; Bolduc, David M; Brower, Evan T; Chaves-Moreira, Daniele; Allaire, Marc; Kinzler, Kenneth W; Jennings, Ian G; Thompson, Philip E; Cole, Philip A; Amzel, L Mario; Vogelstein, Bert; Gabelli, Sandra B
Structural basis of nSH2 regulation and lipid binding in PI3Kα Journal Article
In: Oncotarget, vol. 5, no. 14, pp. 5198-208, 2014, ISSN: 1949-2553.
Abstract | Links | BibTeX | Tags: Amino Acid Sequence, Animals, Binding Sites, Boron Compounds, Models, Molecular, Molecular Sequence Data, Phosphatidylinositol 3-Kinases, Protein Binding, Protein Conformation, Sf9 Cells, Signal Transduction, Spodoptera, src Homology Domains
@article{1299980,
title = {Structural basis of nSH2 regulation and lipid binding in PI3Kα},
author = {Michelle S Miller and Oleg Schmidt-Kittler and David M Bolduc and Evan T Brower and Daniele Chaves-Moreira and Marc Allaire and Kenneth W Kinzler and Ian G Jennings and Philip E Thompson and Philip A Cole and L Mario Amzel and Bert Vogelstein and Sandra B Gabelli},
doi = {10.18632/oncotarget.2263},
issn = {1949-2553},
year = {2014},
date = {2014-07-01},
journal = {Oncotarget},
volume = {5},
number = {14},
pages = {5198-208},
abstract = {We report two crystal structures of the wild-type phosphatidylinositol 3-kinase α (PI3Kα) heterodimer refined to 2.9 Å and 3.4 Å resolution: the first as the free enzyme, the second in complex with the lipid substrate, diC4-PIP$_2$, respectively. The first structure shows key interactions of the N-terminal SH2 domain (nSH2) and iSH2 with the activation loop that suggest a mechanism by which the enzyme is inhibited in its basal state. In the second structure, the lipid substrate binds in a positively charged pocket adjacent to the ATP-binding site, bordered by the P-loop, the activation loop and the iSH2 domain. An additional lipid-binding site was identified at the interface of the ABD, iSH2 and kinase domains. The ability of PI3Kα to bind an additional PIP$_2$ molecule was confirmed in vitro by fluorescence quenching experiments. The crystal structures reveal key differences in the way the nSH2 domain interacts with wild-type p110α and with the oncogenic mutant p110αH1047R. Increased buried surface area and two unique salt-bridges observed only in the wild-type structure suggest tighter inhibition in the wild-type PI3Kα than in the oncogenic mutant. These differences may be partially responsible for the increased basal lipid kinase activity and increased membrane binding of the oncogenic mutant.},
keywords = {Amino Acid Sequence, Animals, Binding Sites, Boron Compounds, Models, Molecular, Molecular Sequence Data, Phosphatidylinositol 3-Kinases, Protein Binding, Protein Conformation, Sf9 Cells, Signal Transduction, Spodoptera, src Homology Domains},
pubstate = {published},
tppubtype = {article}
}
We report two crystal structures of the wild-type phosphatidylinositol 3-kinase α (PI3Kα) heterodimer refined to 2.9 Å and 3.4 Å resolution: the first as the free enzyme, the second in complex with the lipid substrate, diC4-PIP$_2$, respectively. The first structure shows key interactions of the N-terminal SH2 domain (nSH2) and iSH2 with the activation loop that suggest a mechanism by which the enzyme is inhibited in its basal state. In the second structure, the lipid substrate binds in a positively charged pocket adjacent to the ATP-binding site, bordered by the P-loop, the activation loop and the iSH2 domain. An additional lipid-binding site was identified at the interface of the ABD, iSH2 and kinase domains. The ability of PI3Kα to bind an additional PIP$_2$ molecule was confirmed in vitro by fluorescence quenching experiments. The crystal structures reveal key differences in the way the nSH2 domain interacts with wild-type p110α and with the oncogenic mutant p110αH1047R. Increased buried surface area and two unique salt-bridges observed only in the wild-type structure suggest tighter inhibition in the wild-type PI3Kα than in the oncogenic mutant. These differences may be partially responsible for the increased basal lipid kinase activity and increased membrane binding of the oncogenic mutant.