title: EHD3 Protein Is Required for Tubular Recycling Endosome Stabilization, and an Asparagine-Glutamic Acid Residue Pair within Its Eps15 Homology (EH) Domain Dictates Its Selective Binding to NPF Peptides.
abstract: An elaborate network of dynamic lipid membranes, termed tubular recycling endosomes (TRE), coordinates the process of endocytic recycling in mammalian cells. The C-terminal Eps15 homology domain (EHD)-containing proteins have been implicated in the bending and fission of TRE, thus regulating endocytic recycling. EHD proteins have an EH domain that interacts with proteins containing an NPF motif. We found that NPF-containing EHD1 interaction partners such as molecules interacting with CasL-like1 (MICAL-L1) and Syndapin2 are essential for TRE biogenesis. Also crucial for TRE biogenesis is the generation of phosphatidic acid, an essential lipid component of TRE that serves as a docking point for MICAL-L1 and Syndapin2. EHD1 and EHD3 have 86% amino acid identity; they homo- and heterodimerize and partially co-localize to TRE. Despite their remarkable identity, they have distinct mechanistic functions. EHD1 induces membrane vesiculation, whereas EHD3 supports TRE biogenesis and/or stabilization by an unknown mechanism. While using phospholipase D inhibitors (which block the conversion of glycerophospholipids to phosphatidic acid) to deplete cellular TRE, we observed that, upon inhibitor washout, there was a rapid and dramatic regeneration of MICAL-L1-marked TRE. Using this "synchronized" TRE biogenesis system, we determined that EHD3 is involved in the stabilization of TRE rather than in their biogenesis. Moreover, we identify the residues Ala-519/Asp-520 of EHD1 and Asn-519/Glu-520 of EHD3 as defining the selectivity of these two paralogs for NPF-containing binding partners, and we present a model to explain the atomic mechanism and provide new insight for their differential roles in vesiculation and tubulation, respectively.
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870.
authors.forename: Kriti
authors.initials: K
authors.lastname: Bahl
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Xie
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870.
authors.forename: Gaelle
authors.initials: G
authors.lastname: Spagnol
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870.
authors.forename: Paul
authors.initials: P
authors.lastname: Sorgen
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870.
authors.forename: Naava
authors.initials: N
authors.lastname: Naslavsky
authors.affiliation: From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870 scaplan@unmc.edu.
authors.forename: Steve
authors.initials: S
authors.lastname: Caplan
mesh_terms: D001216:Asparagine / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000235:genetics / Q000378:metabolism*; D005973:Glutamine / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008563:Membrane Lipids / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C120700:EHD1 protein, human; C406447:EHD3 protein, human; D008563:Membrane Lipids; D010455:Peptides; D033921:Vesicular Transport Proteins; D005973:Glutamine; D001216:Asparagine
keywords: EHD1; EHD3; MICAL-L1; NMR; Rabankyrin-5; endosome; receptor recycling; trafficking; tubular recycling endosome; vesicles