Molecular Basis for Cooperative Binding of Anionic Phospholipids to the PH Domain of the Arf GAP ASAP1

Xiaoying Jian; Wai-Kwan Tang; Peng Zhai; Neeladri Sekhar Roy; Ruibai Luo; James M Gruschus; Marielle E Yohe; Pei-Wen Chen; Yifei Li; R Andrew Byrd; Di Xia; Paul A Randazzo

doi:10.1016/j.str.2015.08.008

Molecular Basis for Cooperative Binding of Anionic Phospholipids to the PH Domain of the Arf GAP ASAP1

Structure. 2015 Nov 3;23(11):1977-88. doi: 10.1016/j.str.2015.08.008. Epub 2015 Sep 10.

Authors

Affiliations

¹ Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
² Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
³ Laboratory of Structural Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
⁴ Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
⁵ Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
⁶ Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; Laboratory of Cell Biology, National Cancer Institute, Building 37, Room 2122, Bethesda, MD 20892, USA. Electronic address: dixia@helix.nih.gov.
⁷ Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Building 37, Room 2042, Bethesda, MD 20892, USA. Electronic address: randazzp@mail.nih.gov.

Abstract

We have defined the molecular basis for association of the PH domain of the Arf GAP ASAP1 with phospholipid bilayers. Structures of the unliganded and dibutyryl PtdIns(4,5)P2-bound PH domain were solved. PtdIns(4,5)P2 made contact with both a canonical site (C site) and an atypical site (A site). We hypothesized cooperative binding of PtdIns(4,5)P2 to the C site and a nonspecific anionic phospholipid to the A site. PtdIns(4,5)P2 dependence of binding to large unilamellar vesicles and GAP activity was sigmoidal, consistent with cooperative sites. In contrast, PtdIns(4,5)P2 binding to the PH domain of PLC δ1 was hyperbolic. Mutation of amino acids in either the C or A site resulted in decreased PtdIns(4,5)P2-dependent binding to vesicles and decreased GAP activity. The results support the idea of cooperative phospholipid binding to the C and A sites of the PH domain of ASAP1. We propose that the mechanism underlies rapid switching between active and inactive ASAP1.

Publication types

Research Support, N.I.H., Intramural

MeSH terms

Adaptor Proteins, Signal Transducing / chemistry*
Adaptor Proteins, Signal Transducing / metabolism
Amino Acid Sequence
Binding Sites
Humans
Molecular Docking Simulation
Molecular Sequence Data
Phosphatidylinositol 4,5-Diphosphate / chemistry
Phosphatidylinositol 4,5-Diphosphate / metabolism*
Protein Binding

Substances

ASAP1 protein, human
Adaptor Proteins, Signal Transducing
Phosphatidylinositol 4,5-Diphosphate

Abstract

Publication types

MeSH terms

Substances

Grants and funding