数据之源，洞见之始

Mitochondrion outer membrane

The mitochondrial outer membrane serves as a highly permeable barrier, permitting passive diffusion of small metabolites and ions via porins (β-barrel proteins) while restricting larger proteins. Crucially, it functions as a key regulatory site for apoptosis, enabling the release of pro-apoptotic factors (e.g., cytochrome c) from the intermembrane space into the cytosol upon cellular stress, thereby initiating programmed cell death. Its structural and functional integrity is essential for mitochondrial homeostasis, metabolite exchange, and cell fate decisions.