Common lysosomal markers for immunofluorescence studies are LAMP1, CD63 and lysotracker which can also stain late endosomes. Can anyone suggest a marker/dye that is very specific for lysosomes?
Lysotracker stains acidic organelles and we see that it stains late endosomes as well. My studies require proper distinction between the two which is why Iam looking for something that stains only the lysosomes and not the late endosomes. I came across some stain/dye a while ago which stains lysosomes specifically based on the principle of presence of acid hydrolases present in it but am unable to track the article.
CD63 (Lamp3) is more late endosomal and it's true that finding a good specific lysosomal marker is not that easy. A double staining lysotracker + CD63 would allow the discrimination between late endosomes and lysosomes: lysosomes would be lysotracker-positive but almost CD63-negative. Alternatively, you could try to label lysosomal enzymes, such as Cathepsin D, but not sure if there is an good commercial antibody raised against it...
"To functionally assess if LAP increases exposure of L.m. to lysosomal acid hydrolases, we labeled L.m. with 5-dodecanoylaminofluorescein-di-β-D-galactopyranoside (C12FDG) that becomes fluorescent upon cleavage by the lysosomal acid hydrolase β-galactosidase."