Fig. 4. Colocalization of the autophagic marker LC3-GFP and LTR on nutrient depletion in controls and LAMP1 or LAMP2 knockdown cells. HeLa cells were transfected with siRNA specific for the indicated gene products (24 hours), transfected with LC3-GFP (24 hours), and cultured in complete medium (CM) of nutrient-free medium (NF) for 4 hours, followed by staining with lysotracker (LTR, 30 minutes) red and confocal scanning fluorescence microscopy. Representative cells are shown in A. Bar, 10 µm. The graphs (right panels) represent the fluorescence distribution determined for section of the cells, as indicated by the orientation of the arrow. The degree of colocalization (X±s.d.) was determined by image analysis for 50 cells each, as indicated in Materials and Methods.