Image indicative of 24 h autophagic activity of human colon carcinoma HCT 116 cell co-transfected with a RFP-LC3-encoding plasmid and a SIRT1 variant with a mutation in the nuclear localization signal fused to GFP (mtNLS GFTP-SIRT1) which is virtually restricted to the cytoplasm. Confocal fluorescent images were captured using a confocal fluorescence microscope (TCS SP2; Leica) fitted with an Apochromat 63× 1.3 NA immersion objective. Images were acquired with a camera (DFC 350 FX 1.8.0; Leica) using LAS AF software (Leica) and processed with Photoshop (CS2; Adobe) software. Specifically, picture processing involved cropping of representative areas and linear adjustments of contrast and brightness and was performed using Photoshop (with equal adjustment parameters for all pictures); no explicit γ correction was used. Image: Figure 8C, bottom panel, in Morselli et al. J Cell Biol 192: 615-629