The effect of UPR on intracellular intake is specific to <i>C</i>. <i>jejuni</i> infection.

(A) HeLa cells transfected with pENTR-PERK vector, pENTR-IRE1 vector pENTR-ATF6 vector, or non-target shRNA control vector were infected by C. jejuni for 3 h or by S. Enteritidis for 1 h or treated with 0.1 mg/mL 10 kDa FITC-dextran for 2 h. After infection, intracellular bacteria numbers were estimated using a gentamicin protection assay. FITC-dextran uptake was measured by fluorescence. (B) HeLa cells transfected with pENTR-PERK vector or non-target shRNA control vector were treated with MβCD (7.5 mM) for 1 h, the number of intracellular bacteria was estimated using the gentamicin protection assay. Asterisks denote significant differences versus control groups (n.s., not significant, *p < 0.05, **p < 0.01, by t-test, n = 6). Each experiment was repeated three times.