FIGURE 2:
Palmitate localizes to the ER and represses global initiation of translation. (A) Electron microscopy showing ultrastructures of HepG2 cells treated with vehicle, oleate, or palmitate for the indicated times. (B, C) Spinning disk confocal images of CLICK-IT–labeled palmitic acid, azide tagged with Alexa Fluor 488 alklyne, showing colocalization with the ER (calnexin) or PERK. The percentage colocalization of palmitate with calnexin and PERK is illustrated to the right. (D–F) Polysome profiles of lysates prepared from HepG2 cells treated with vehicle, palmitate, oleate, or tunicamycin for 12 h. (G) Polysome profile of PERK KO HepG2 cells treated with either vehicle or palmitate for 12 h. (H) Cell death of PERK KO HepG2 cells, as measured by LDH release, treated or not with palmitate. (I) Immunoblot analysis of control and PERK KO HepG2 cells after 12-h treatment with vehicle or palmitate.