Fig. 3. Cell type, regional, and synaptic specificities of protein lifetime changes in the aged versus the young adult brain.

(A) Heatmap summarizing lifetime changes for 1143 proteins in the aged brain with respect to the young adult brain [representing the fold change expressed as log₂ (log₂FC) between 21- and 5-month-old mice as a z score], showing modifications in lifetimes that in aging affect more specifically either brain cortex or cerebellum. Because of space limitations, only the 15 rSL proteins (top) or the 15 rLL proteins in the cortex versus the cerebellum (bottom) are shown (for a detailed list, see table S6). (B) Gene set enrichment analysis of (A), summarizing the molecular function, biological process, and cellular component of the gene ontologies (GOs) significantly enriched with an FDR of <0.05 (for the whole results, see table S6). (C and D) Comparison [represented as in (A) and (B)] between lifetime changes in the total homogenate and the respective enriched synaptic fractions that were obtained as previously described (19).