This study provides a comprehensive analysis of the molecular composition and functional diversity of mouse mitochondria across different tissues. The researchers performed a proteomic survey of mitochondria from brain, heart, kidney, and liver, identifying 399 protein clusters, 236 of which were previously annotated as mitochondrial proteins. This analysis identified 163 novel mitochondrial proteins, bringing the total number of known mitochondrial proteins to 591. The protein expression data were compared with RNA abundance profiles, revealing tissue-specific differences in organelle composition. The study also identified subnetworks of mitochondrial genes with correlated expression patterns, suggesting shared regulatory mechanisms. Additionally, the researchers identified a "mitochondrial neighborhood" of genes that are co-regulated with mitochondrial genes, providing insights into the functional organization of mitochondrial processes. The findings contribute to a better understanding of mitochondrial biology and its role in human diseases.This study provides a comprehensive analysis of the molecular composition and functional diversity of mouse mitochondria across different tissues. The researchers performed a proteomic survey of mitochondria from brain, heart, kidney, and liver, identifying 399 protein clusters, 236 of which were previously annotated as mitochondrial proteins. This analysis identified 163 novel mitochondrial proteins, bringing the total number of known mitochondrial proteins to 591. The protein expression data were compared with RNA abundance profiles, revealing tissue-specific differences in organelle composition. The study also identified subnetworks of mitochondrial genes with correlated expression patterns, suggesting shared regulatory mechanisms. Additionally, the researchers identified a "mitochondrial neighborhood" of genes that are co-regulated with mitochondrial genes, providing insights into the functional organization of mitochondrial processes. The findings contribute to a better understanding of mitochondrial biology and its role in human diseases.