Multi cell line analysis of lysosomal proteomes reveals unique features and novel lysosomal proteins

Abstract

Lysosomes play a key role in the regulation of cellular metabolism and are increasingly recognized as highly active and diverse organelles which are involved in a large variety of processes. Their essential role is exemplified by the detrimental consequences of lysosomal malfunction, which can result in lysosomal storage disorders, neurodegenerative diseases, and cancer. Using lysosome enrichment and mass spectrometry, we investigated the lysosomal proteomes of six common cell lines. We provide first evidence for cell-type specific differences of lysosomes on a large scale, showing highly variable levels of distinct lysosomal proteins within one cell type, while others are highly conserved among cell lines. Using stable isotope labelling and bimodal distribution analysis, we identify high confidence lysosomal proteins for each cell line. Multi cell line correlation of these data reveals potential novel lysosomal proteins, and we confirm lysosomal localization for five candidates. All data are available via ProteomeXchange with identifier PXD020600.