Core Viewpoint - The research conducted by the team led by Academician Shi Yigong reveals the structural basis of BAX pore formation, which is crucial for understanding mitochondrial outer membrane permeability during apoptosis [2][3]. Group 1: Research Findings - The study elucidates the assembly principles of various BAX oligomers, providing a structural foundation for BAX-mediated mitochondrial outer membrane permeability [3]. - The research team purified recombinant human BAX protein and confirmed its membrane permeability activity through cytochrome c release experiments based on liposomes [5]. - The activated BAX oligomers were extracted and purified from overexpressed BAX protein in human embryonic kidney 293F cells for cryo-electron microscopy analysis [6]. Group 2: Structural Insights - The study identified that the dimer of BAX is the basic repeating structural unit of its various oligomeric forms (arc, line, and ring) [7]. - The structure of the BAX repeating unit revealed interactions within and between dimers, with the α9 helix facilitating end-to-end stacking to form linear, arc, polygonal, and ring shapes [7]. - Structural characterization was performed on quadrilateral, pentagonal, hexagonal, and heptagonal forms composed of 16, 20, 24, and 28 BAX monomers, respectively [7]. Group 3: Implications of Findings - The results clarify how activated BAX oligomers permeabilize (or rupture) the mitochondrial outer membrane and explain how different shapes (arc, line, and ring) are assembled from the same repeating unit [9].