title: Echovirus 1 entry into polarized Caco-2 cells depends on dynamin, cholesterol, and cellular factors associated with macropinocytosis.
abstract: Enteroviruses invade their hosts by crossing the intestinal epithelium. We have examined the mechanism by which echovirus 1 (EV1) enters polarized intestinal epithelial cells (Caco-2). Virus binds to VLA-2 on the apical cell surface and moves rapidly to early endosomes. Using inhibitory drugs, dominant negative mutants, and small interfering RNAs (siRNAs) to block specific endocytic pathways, we found that virus entry requires dynamin GTPase and membrane cholesterol but is independent of both clathrin- and caveolin-mediated endocytosis. Instead, infection requires factors commonly associated with macropinocytosis, including amiloride-sensitive Na(+)/H(+) exchange, protein kinase C, and C-terminal-binding protein-1 (CtBP1); furthermore, EV1 accumulates rapidly in intracellular vesicles with dextran, a fluid-phase marker. These results suggest a role for macropinocytosis in the process by which EV1 enters polarized cells to initiate infection.
authors.affiliation: Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Sophie E
authors.initials: SE
authors.lastname: Krieger
authors.forename: Chonsaeng
authors.initials: C
authors.lastname: Kim
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Varpu
authors.initials: V
authors.lastname: Marjomaki
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Bergelson
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D018938:Caco-2 Cells; D002784:Cholesterol / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism*; D029822:Enterovirus B, Human / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology* / Q000821:virology; D054884:Host-Pathogen Interactions; D006801:Humans; D010873:Pinocytosis; D011493:Protein Kinase C / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D022161:Transport Vesicles / Q000821:virology; D053586:Virus Internalization
chemical_list: D004268:DNA-Binding Proteins; D017923:Sodium-Hydrogen Exchangers; D002784:Cholesterol; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein; D011493:Protein Kinase C; D034281:Dynamins