GAPDH and systemic lupus erythematosus: While no change of expression of any of these markers was detectable when total homogenate (HOM) fractions from healthy (CBA/J) and lupus (MRL/lpr) mice were analyzed (Figure 2 and Figure S2), a raised expression of LAMP1, LAMP2A and GAPDH was visualized in lupus lysosome-enriched fractions compared to control ones (Figure 2; 6 mice per group).