title: Structural basis for PI(4)P-specific membrane recruitment of the Legionella pneumophila effector DrrA/SidM.
abstract: Recruitment of the Legionella pneumophila effector DrrA to the Legionella-containing vacuole, where it activates and AMPylates Rab1, is mediated by a P4M domain that binds phosphatidylinositol 4-phosphate [PI(4)P] with high affinity and specificity. Despite the importance of PI(4)P in Golgi trafficking and its manipulation by pathogens, the structural bases for PI(4)P-dependent membrane recruitment remain poorly defined. Here, we determined the crystal structure of a DrrA fragment including the P4M domain in complex with dibutyl PI(4)P and investigated the determinants of phosphoinositide recognition and membrane targeting. Headgroup recognition involves an elaborate network of direct and water-mediated interactions with basic and polar residues in the context of a deep, constrictive binding pocket. An adjacent hydrophobic helical element packs against the acyl chains and inserts robustly into PI(4)P-containing monolayers. The structural, biochemical, and biophysical data reported here support a detailed structural mechanism for PI(4)P-dependent membrane targeting by DrrA.
authors: Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors: Claudia M
authors: CM
authors: Del Campo
authors: Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors: Ashwini K
authors: AK
authors: Mishra
authors: Institute for Medicine and Engineering and Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors: Yu-Hsiu
authors: YH
authors: Wang
authors: Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, CT 06536, USA.
authors: Craig R
authors: CR
authors: Roy
authors: Institute for Medicine and Engineering and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA.
authors: Paul A
authors: PA
authors: Janmey
authors: Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA. Electronic address: david.lambright@umassmed.edu.
authors: David G
authors: DG
authors: Lambright
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016952:Legionella pneumophila / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D020662:Guanine Nucleotide Exchange Factors; D018129:Phosphatidylinositol Phosphates; C539733:SidM protein, Legionella pneumophila; C037178:phosphatidylinositol 4-phosphate