FIG. 3.
Calnexin associates with the endo H-sensitive form of G1. Virus-infected BHK21 cells were labeled with [35S]methionine for 10 min at 14 h postinfection and chased for the indicated times. Cells were lysed with 1% digitonin and first precipitated with anticalnexin antiserum (A). Proteins remaining in the supernatants were reprecipitated with a mixture of poly- and monoclonal anti-G1 antibodies (B). Half of the samples were treated with endo H, and half were left untreated. Proteins were analyzed on an SDS–10% polyacrylamide gel under reducing conditions, followed by fluorography. The positions of calnexin (CNX), G1, G2, and BiP (asterisk), as well as molecular weight markers (in thousands), are indicated. MOCK, immunoprecipitated proteins from mock-infected cells; G1S and G2S, endo H-sensitive forms of the spike proteins G1 and G2, respectively; G1R, an endo H-resistant form of G1.