title: MHC class I molecules are enriched in caveolae but do not enter with simian virus 40.
abstract: Simian virus 40 (SV40) binds to MHC class I molecules anywhere on the cell surface and then enters through caveolae. The fate of class I molecules after SV40 binding is not known. Sensitivity of 125I-surface-labelled class I molecules to papain cleavage was used to distinguish internalized class I molecules from class I molecules remaining at the cell surface. Whereas the caveolae-enriched membrane microdomain was found to also be enriched for class I molecules, no internalized papain-resistant 125I-surface-labelled class I molecules could be detected at any time in either control cells or in cells preadsorbed with saturating amounts of SV40. Instead, 125I-surface-labelled class I molecules, as well as preadsorbed 125I-labelled anti-class I antibodies, accumulated in the medium, coincident with the turnover of class I molecules at the cell surface. The class I heavy chains that accumulated in the medium were truncated and their release was specifically prevented by the metalloprotease inhibitor 1,10-phenanthroline. Thus, whereas class I molecules mediate SV40 binding, they do not appear to mediate SV40 entry.
authors.affiliation: Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, 01003, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Anderson
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: L C
authors.initials: LC
authors.lastname: Norkin
mesh_terms: D000818:Animals; D051242:Caveolin 1; D022461:Caveolins; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D013539:Simian virus 40 / Q000378:metabolism* / Q000502:physiology
chemical_list: D051242:Caveolin 1; D022461:Caveolins; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins