The rubella virus E1 glycoprotein is arrested in a novel post-ER, pre- Golgi compartment

Human anti-rubella virus serum was obtained from Dr. Aubrey Tingle (University of British Columbia, Vancouver, Canada) or was purchased from Vital Blood Products (Caiabasa, CA). Mouse monoclonais I-I2C213 and H4C52 to RV E1 were kindly provided by Dr. John Safford (Abbott Laboratories), and 21BgH and 3D9F (21) were produced and characterized in the lab of Dr. Shirley Gillum (University of British Columbia, Vancouver). Rabbit anti-ER serum (33) was from Dr. Daniel Louvard (Pasteur Institute, Paris), and rabbit anti-lgpl20 serum (15) was provided by Dr. W. A. Dunn (University of Florida, Gainesville, Florida). Rabbit antibodies to mannose-6-phosphate receptor were characterized previously (9) . Rat monoclonal anti-BiP (5) was provided by Dr. Linda Hendershot (St. Judes Hospital), and afffinity-purified rabbit anti-cathepsin D was from Dr. Keitaro Kato (Kyushu University, Kyushu, Japan). Dr. David Meyers (University of California, Los Angeles, CA) kindly supplied us with anti-160-kD ER membrane protein serum. Rabbit anti-PDI antibody (62) was obtained from Dr. Stephen Fuller (European Molecular Biology Laboratory, Heidelberg, Germany). Rabbit anti-serum to gp58 was obtained from Jaakko Saraste (Ludwig Cancer Institute, Stockholm, Sweden), and mouse polyclonai antibody to gp58 was prepared by Dr. Linda Hendricks (this lab). Rabbit antiserum to a-mannosidase II was prepared by Dr. Linda Handricks (this lab) and Dr. Kelley Moremen (University of Georgia, Athens, GA) using antigen prepared as described (38) . Mouse mAb to VSV G protein was a kind gift from Dr. William Baich (Scripps Clinic and Research Foundation, La Jolla, CA).