Rpmi 1640 medium with l glutamine and sodium bicarbonate

siRNAs: Silencer Select GAPDH Positive Control siRNA was purchased from Thermo Fisher Scientific (San Jose, CA, USA). These siRNAs were used after labeling with Cy5 using the Label IT siRNA Tracker Cy5 Kit (Mirus Bio LLC, Madison, WI, USA). Peptides: The synthetic peptide Q-tag-R9-HA (5′-Acetyl-LLQGRRRRRRRRRYPYDVPDYA-COOH-3′) was purchased from Eurofins Genomics (Ebersberg, Germany). Cell lines: A431 human epidermoid carcinoma cells were obtained from the Cell Resource Center for Biomedical Research, Institute of Development, Aging, and Cancer, Tohoku University (Sendai, Japan). HEK293 cells were obtained from the Japanese Collection of Research Bioresources Cell bank (Osaka, Japan). These cells were cultured in RPMI 1640 medium with L-glutamine and sodium bicarbonate (liquid, sterile-filtered, suitable for cell culture; Sigma Aldrich, St. Louis, MO, USA) supplemented with 10% fetal bovine serum (Biowest, France) and 1 × Anti-Anti (Gibco, Thermo Fisher Scientific, Waltham, MA, USA).