title: EHDS are serine phosphoproteins: EHD1 phosphorylation is enhanced by serum stimulation.
abstract: Endocytic processes are mediated by multiple protein-protein interacting modules and regulated by phosphorylation and dephosphorylation. The Eps15 homology domain containing protein 1 (EHD1) has been implicated in regulating recycling of proteins, internalized both in clathrin-dependent and clathrin-independent endocytic pathways, from the recycling compartment to the plasma membrane. EHD1 was found in a complex with clathrin, adaptor protein complex-2 (AP-2) and insulin-like growth factor-1 receptor (IGF-1R), and was shown to interact with Rabenosyn-5, SNAP29, EHBP1 (EH domain binding protein 1) and syndapin I and II. In this study, we show that EHD1, like the other human EHDs, undergoes serine-phosphorylation. Our results also indicate that EHD1 is a serum-inducible serine-phosphoprotein and that PKC (protein kinase C) is one of its kinases. In addition, we show that inhibitors of clathrin-mediated endocytosis decrease EHD1 phosphorylation, while inhibitors of caveolinmediated endocytosis do not affect EHD1 phosphorylation. The results of experiments in which inhibitors of endocytosis were employed strongly suggest that EHD1 phosphorylation occurs between early endosomes and the endocytic recycling compartment.
authors.affiliation: Department of Cell Research and Immunology, Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Boris
authors.initials: B
authors.lastname: Fichtman
authors.forename: Liat
authors.initials: L
authors.lastname: Ravid
authors.forename: Debora
authors.initials: D
authors.lastname: Rapaport
authors.forename: Mia
authors.initials: M
authors.lastname: Horowitz
mesh_terms: D000730:Androstadienes / Q000378:metabolism; D000818:Animals; D022461:Caveolins / Q000378:metabolism; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D006801:Humans; D015739:Nocodazole / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D044967:Serum / Q000378:metabolism*; D050257:Tubulin Modulators / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D022461:Caveolins; D002966:Clathrin; C120700:EHD1 protein, human; D010750:Phosphoproteins; D020033:Protein Isoforms; D047428:Protein Kinase Inhibitors; D050257:Tubulin Modulators; D033921:Vesicular Transport Proteins; D012694:Serine; D011493:Protein Kinase C; D015739:Nocodazole; D000077191:Wortmannin