Lysosomes possess high SM content. HeLa cells were treated as described in ( a ), and lysosomal-associated membrane protein 1 (LAMP1) was stained by an anti-LAMP1 primary and a CF568 secondary antibody. Images recorded in the FRET channel were multiplied by factor 2 and divided by the BODIPY-FL (donor) channel resulting in images that describe the metabolic state of the molecule. n = 1. Scale bars: 50 m (~ 12.5 m with 4-fold expansion factor) and 12 m for zoomed images (~ 3 m with 4-fold expansion factor).
