title: Limited transferrin receptor clustering allows rapid diffusion of canine parvovirus into clathrin endocytic structures.
abstract: Viral pathogens usurp cell surface receptors to access clathrin endocytic structures, yet the mechanisms of virus incorporation into these structures remain incompletely understood. Here we used fluorescence microscopy to directly visualize the association of single canine parvovirus (CPV) capsids with cellular transferrin receptors (TfR) on the surfaces of live feline cells and to monitor how these CPV-TfR complexes access endocytic structures. We found that most capsids associated with fewer than five TfRs and that ∼25% of TfR-bound capsids laterally diffused into assembling clathrin-coated pits less than 30 s after attachment. Capsids that did not encounter a coated pit dissociated from the cell surface with a half-life of ∼30 s. Together, our results show how CPV exploits the natural mechanism of TfR endocytosis to engage the clathrin endocytic pathway and reveal that the low affinity of capsids for feline TfRs limits the residence time of capsids on the cell surface and thus the efficiency of virus internalization.
authors.affiliation: Immune Disease Institute and Program in Cellular and Molecular Medicine at Children's Hospital Boston, Boston, Massachusetts, USA.
authors.forename: David K
authors.initials: DK
authors.lastname: Cureton
authors.forename: Carole E
authors.initials: CE
authors.lastname: Harbison
authors.forename: Emanuele
authors.initials: E
authors.lastname: Cocucci
authors.forename: Colin R
authors.initials: CR
authors.lastname: Parrish
authors.forename: Tom
authors.initials: T
authors.lastname: Kirchhausen
mesh_terms: D000818:Animals; D002213:Capsid / Q000378:metabolism; D002415:Cats; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D004058:Diffusion; D004285:Dogs; D004705:Endocytosis; D007700:Kinetics; D017993:Parvovirus, Canine / Q000378:metabolism*; D011485:Protein Binding; D011990:Receptors, Transferrin / Q000737:chemistry* / Q000378:metabolism; D011991:Receptors, Virus / Q000378:metabolism; D019065:Virus Assembly; D053586:Virus Internalization
chemical_list: D002966:Clathrin; D011990:Receptors, Transferrin; D011991:Receptors, Virus