title: Heterotypic Sam-Sam association between Odin-Sam1 and Arap3-Sam: binding affinity and structural insights.
abstract: Arap3 is a phosphatidylinositol 3 kinase effector protein that plays a role as GTPase activator (GAP) for Arf6 and RhoA. Arap3 contains a sterile alpha motif (Sam) domain that has high sequence homology with the Sam domain of the EphA2-receptor (EphA2-Sam). Both Arap3-Sam and EphA2-Sam are able to associate with the Sam domain of the lipid phosphatase Ship2 (Ship2-Sam). Recently, we reported a novel interaction between the first Sam domain of Odin (Odin-Sam1), a protein belonging to the ANKS (ANKyrin repeat and Sam domain containing) family, and EphA2-Sam. In our latest work, we applied NMR spectroscopy, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) to characterize the association between Arap3-Sam and Odin-Sam1. We show that these two Sam domains interact with low micromolar affinity. Moreover, by means of molecular docking techniques, supported by NMR data, we demonstrate that Odin-Sam1 and Arap3-Sam might bind with a topology that is common to several Sam-Sam complexes. The revealed structural details form the basis for the design of potential peptide antagonists that could be used as chemical tools to investigate functional aspects related to heterotypic Arap3-Sam associations.
authors.affiliation: Department of Biological Sciences, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Flavia A
authors.initials: FA
authors.lastname: Mercurio
authors.forename: Daniela
authors.initials: D
authors.lastname: Marasco
authors.forename: Luciano
authors.initials: L
authors.lastname: Pirone
authors.forename: Pasqualina L
authors.initials: PL
authors.lastname: Scognamiglio
authors.forename: Emilia M
authors.initials: EM
authors.lastname: Pedone
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pellecchia
authors.forename: Marilisa
authors.initials: M
authors.lastname: Leone
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D062105:Molecular Docking Simulation; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: C557872:ANKS1A protein, human; C446512:ARAP3 protein, human; D048868:Adaptor Proteins, Signal Transducing; D020690:GTPase-Activating Proteins