title: The giardial ENTH protein participates in lysosomal protein trafficking and endocytosis.
abstract: In the protozoa parasite Giardia lamblia, endocytosis and lysosomal protein trafficking are vital parasite-specific processes that involve the action of the adaptor complexes AP-1 and AP-2 and clathrin. In this work, we have identified a single gene in Giardia encoding a protein containing an ENTH domain that defines monomeric adaptor proteins of the epsin family. This domain is present in the epsin or epsin-related (epsinR) adaptor proteins, which are implicated in endocytosis and Golgi-to-endosome protein trafficking, respectively, in other eukaryotic cells. We found that GlENTHp (for G. lamblia ENTH protein) localized in the cytosol, strongly interacted with PI3,4,5P3, was associated with the alpha subunit of AP-2, clathrin and ubiquitin and was involved in receptor-mediated endocytosis. It also bonded PI4P, the gamma subunit of AP-1 and was implicated in ER-to-PV trafficking. Alteration of the GlENTHp function severely affected trophozoite growth showing an unusual accumulation of dense material in the lysosome-like peripheral vacuoles (PVs), indicating that GlENTHp might be implicated in the maintenance of PV homeostasis. In this study, we showed evidence suggesting that GlENTHp might function as a monomeric adaptor protein supporting the findings of other group indicating that GlENTHp might be placed at the beginning of the ENTH family.
authors.affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina.
authors.forename: Constanza
authors.initials: C
authors.lastname: Feliziani
authors.affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina.
authors.forename: Nahuel
authors.initials: N
authors.lastname: Zamponi
authors.affiliation: Molecular Biology Division, Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario, CONICET, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: Gottig
authors.affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Rópolo
authors.affiliation: Serviço de Microscopia Eletrônica, Centro de Pesquisas Gonçalo Moniz, FIOCRUZ-BA, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Lanfredi-Rangel
authors.affiliation: Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina. Electronic address: ctouz@immf.uncor.edu.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Touz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004705:Endocytosis / Q000235:genetics; D016829:Giardia lamblia / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D030781:Organisms, Genetically Modified; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013869:Thiolester Hydrolases / Q000737:chemistry / Q000502:physiology*
chemical_list: D013869:Thiolester Hydrolases
keywords: ENTH motif; Endosome; Giardia lamblia; Lysosome