Monoclonal anti-rbet1 antibodies were described previously (Hay et al., 1998 (link)). Affinity-purified polyclonal anti-p24, -sec23, and -β-COP from our laboratory were described previously (Bentley et al., 2006 (link)). Anti-sec31 was produced in rabbits against the synthetic peptide KLKEIDRTAMQAWSPAQNHPC and then affinity purified using a column of the immobilized peptide. Anti-GM130 and -p115 were a kind gift from Dr. Martin Lowe (University of Manchester, Manchester, United Kingdom). Anti-ALG-2 was a kind gift from Dr. Masayuki Komada (Tokyo Institute of Technology, Tokyo, Japan). Anti-sec16 antibody (KIAA0310) was acquired from Novus Biologicals (Littleton, CO). Anti-GPP130 antibody (PRB144C) was purchased from Covance Research Products (Princeton, NJ). Anti-protein disulfide isomerase (PDI; SPA-890) was from Assay Designs (Ann Arbor, MI). Anti-IP3R-3 (610312) was purchased from BD Biosciences Transduction Laboratories (Lexington, KY). Anti-mannosidase II antibody (MMS-110R-200) was purchased from Covance Research Products. Anti-myc monoclonal antibody (mAb) 9E10 was purified from hybridoma tissue culture supernatant. Secondary antibodies were FITC or Cy3 conjugated and purchased from Jackson ImmunoResearch Laboratories (West Grove, PA).