Lysosomes are a major site of intracellular acidic hydrolase-mediated proteolysis and cellular degradation in a membrane-enclosed organelle. Alternatively, soluble, ubiquitin-bound proteins are degraded via the proteasome, a megadalton protein complex within the cytoplasm. The interplay between both degradation pathways has been of increasing interest in recent years. To determine the effects of proteasome inhibition on the lysosomal compartment, we investigated enriched lysosomal fractions, autophagosomal fractions and immunoprecipitated proteasomes from HEK293 cells after proteasome inibition by MG132 or bortezomib in comparison to the respective fractions from control cells.