title: NMR structure of a heterodimeric SAM:SAM complex: characterization and manipulation of EphA2 binding reveal new cellular functions of SHIP2.
abstract: The sterile alpha motif (SAM) for protein-protein interactions is encountered in over 200 proteins, but the structural basis for its interactions is just becoming clear. Here we solved the structure of the EphA2-SHIP2 SAM:SAM heterodimeric complex by use of NMR restraints from chemical shift perturbations, NOE and RDC experiments. Specific contacts between the protein surfaces differ significantly from a previous model and other SAM:SAM complexes. Molecular dynamics and docking simulations indicate fluctuations in the complex toward alternate, higher energy conformations. The interface suggests that EphA family members bind to SHIP2 SAM, whereas EphB members may not; correspondingly, we demonstrate binding of EphA1, but not of EphB2, to SHIP2. A variant of EphB2 SAM was designed that binds SHIP2. Functional characterization of a mutant EphA2 compromised in SHIP2 binding reveals two previously unrecognized functions of SHIP2 in suppressing ligand-induced activation of EphA2 and in promoting receptor coordinated chemotactic cell migration.
authors.affiliation: Department of Physiology and Biophysics, MetroHealth, Cleveland, OH 44109, USA.
authors.forename: Hyeong J
authors.initials: HJ
authors.lastname: Lee
authors.forename: Prasanta K
authors.initials: PK
authors.lastname: Hota
authors.forename: Preeti
authors.initials: P
authors.lastname: Chugha
authors.forename: Hong
authors.initials: H
authors.lastname: Guo
authors.forename: Hui
authors.initials: H
authors.lastname: Miao
authors.forename: Liqun
authors.initials: L
authors.lastname: Zhang
authors.forename: Soon-Jeung
authors.initials: SJ
authors.lastname: Kim
authors.forename: Lukas
authors.initials: L
authors.lastname: Stetzik
authors.forename: Bing-Cheng
authors.initials: BC
authors.lastname: Wang
authors.forename: Matthias
authors.initials: M
authors.lastname: Buck
mesh_terms: D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D019281:Dimerization; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D015394:Molecular Structure; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D016296:Mutagenesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D036104:Receptor, EphA2 / Q000378:metabolism*
chemical_list: D046912:Multiprotein Complexes; D036104:Receptor, EphA2; D010744:Phosphoric Monoester Hydrolases; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases