title: EHD1 and Eps15 interact with phosphatidylinositols via their Eps15 homology domains.
abstract: The C-terminal Eps15 homology domain-containing protein, EHD1, regulates the recycling of receptors from the endocytic recycling compartment to the plasma membrane. In cells, EHD1 localizes to tubular and spherical recycling endosomes. To date, the mode by which EHD1 associates with endosomal membranes remains unknown, and it has not been determined whether this interaction is direct or via interacting proteins. Here, we provide evidence demonstrating that EHD1 has the ability to bind directly and preferentially to an array of phospholipids, preferring phosphatidylinositols with a phosphate at position 3. Previous studies have demonstrated that EH domains coordinate calcium binding and interact with proteins containing the tripeptide asparagine-proline-phenylalanine (NPF). Using two-dimensional nuclear magnetic resonance analysis, we now describe a new function for the Eps15 homology (EH) domain of EHD1 and show that it is capable of directly binding phosphatidylinositol moieties. Moreover, we have expanded our studies to include the C-terminal EH domain of EHD4 and the second of the three N-terminal EH domains of Eps15 and demonstrated that phosphatidylinositol binding may be a more general property shared by certain other EH domains. Further studies identified a positively charged lysine residue (Lys-483) localized within the third helix of the EH domain, on the opposite face of the NPF-binding pocket, as being critical for the interaction with the phosphatidylinositols.
authors.affiliation: Department of Biochemistry and Molecular Biology and Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870, USA.
authors.forename: Naava
authors.initials: N
authors.lastname: Naslavsky
authors.forename: Juliati
authors.initials: J
authors.lastname: Rahajeng
authors.forename: Sylvie
authors.initials: S
authors.lastname: Chenavas
authors.forename: Paul L
authors.initials: PL
authors.lastname: Sorgen
authors.forename: Steve
authors.initials: S
authors.lastname: Caplan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D011992:Endosomes / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010716:Phosphatidylinositols / Q000737:chemistry* / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C120700:EHD1 protein, human; C486206:EPS15 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D010716:Phosphatidylinositols; D010750:Phosphoproteins; D011994:Recombinant Proteins; D033921:Vesicular Transport Proteins; D002118:Calcium