title: Characterization of human astrovirus cell entry.
abstract: Human astroviruses (HAstV) are a frequent cause of gastroenteritis in young children and immunocompromised patients. To understand the early steps of HAstV infection in the highly permissive Caco-2 cell line, the binding and entry processes of the virus were characterized. The half-time of virus binding to the cell surface was about 10 min, while virus decapsidation took around 130 min. Drugs affecting clathrin-mediated endocytosis, endosome acidification, and actin filament polymerization, as well as those that reduce the presence of cholesterol in the cell membrane, decreased the infectivity of the virus. The infection was also reduced by silencing the expression of the clathrin heavy chain (CHC) by RNA interference or by overexpression of dominant-negative mutants of dynamin 2 and Eps15. Furthermore, the entry of HAstV apparently depends on the maturation of endosomes, since the infection was reduced by silencing the expression of Rab7, a small GTPase involved in the early- to late-endosome maturation. Altogether, our results suggest that HAstV enters Caco-2 cells using a clathrin-dependent pathway and reaches late endosomes to enter cells. Here, we have characterized the mechanism used by human astroviruses, important agents of gastroenteritis in children, to gain entry into their host cells. Using a combination of biochemical and genetic tools, we found that these viruses enter Caco-2 cells using a clathrin-dependent endocytic pathway, where they most likely need to travel to late endosomes to reach the cytoplasm and begin their replication cycle.
authors: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors: Ernesto
authors: E
authors: Méndez
authors: Claudia
authors: C
authors: Muñoz-Yañez
authors: Claudia
authors: C
authors: Sánchez-San Martín
authors: Gabriela
authors: G
authors: Aguirre-Crespo
authors: M del Rocio
authors: Mdel R
authors: Baños-Lara
authors: Michelle
authors: M
authors: Gutierrez
authors: Rafaela
authors: R
authors: Espinosa
authors: Yunuén
authors: Y
authors: Acevedo
authors: Carlos F
authors: CF
authors: Arias
authors: Susana
authors: S
authors: López
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism; D000998:Antiviral Agents / Q000494:pharmacology; D019350:Astroviridae Infections / Q000235:genetics / Q000378:metabolism / Q000821:virology; D002460:Cell Line; D002966:Clathrin / Q000235:genetics / Q000378:metabolism; D034281:Dynamins / Q000235:genetics / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D020868:Gene Silencing; D006801:Humans; D001257:Mamastrovirus / Q000187:drug effects / Q000502:physiology*; D009154:Mutation; D053585:Virus Attachment; D053586:Virus Internalization; D057074:Virus Release; D014779:Virus Replication / Q000187:drug effects; D057646:Virus Uncoating; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D000998:Antiviral Agents; D002966:Clathrin; C486204:EPN2 protein, human; D005656:Fungal Proteins; D000090802:rab7 GTP-Binding Proteins; C000716463:rab7 GTP-binding proteins, human; C014801:alpha-sarcin; D004722:Endoribonucleases; D020691:rab GTP-Binding Proteins; D034281:Dynamins