kifunensine (Calbiochem, Billerica, MA), puromycin (InvivoGen, San Diego, CA), and bafilomycin A1,
MG-132, and DTT (Sigma-Aldrich, St. Louis, MO). For Western blot analyses, the following antibodies
were used: anti-FLAG M1 and anti-tubulin (Sigma-Aldrich), anti–α1-antitrypsin (Dako,
Glostrup, Denmark), anti–14-3-3z and anti-SEL1L (Santa Cruz Biotechnology, Dallas, TX),
anti–S-tag and anti–OS-9 (Abcam, Cambridge, England), anti–GRP94 9G10 and
anti-KDEL (Enzo, Farmingdale, NY), anti-GRP94 (provided by Ineke Braakman, Utrecht University,
Utrecht, Netherlands), anti-HA (Covance, Princeton, NJ), anti-BiP (BD Biosciences, San Jose, CA),
and anti-PERK and anti-JNK (Cell Signaling Technologies, Danvers, MA). Secondary antibodies were
obtained from LI-COR (IRDye 680 and 800 nm, for use with the LI-COR Odyssey system [Lincoln, NE])
and Santa Cruz Biotechnology (horseradish peroxidase conjugated).