Recent insights into bacterial ESCRT-III-mediated membrane remodeling

The ESCRT-III complex is a highly conserved membrane remodeling system known for its essential roles in eukaryotic cellular processes such as endosomal trafficking, multivesicular body (MVB) formation, viral budding, membrane repair, and cytokinesis. These activities are critical for maintaining cellular integrity, and dysfunction in ESCRT-III has been linked to diseases including cancer, viral infection, and neurodegeneration. Recent findings suggest that bacterial homologs such as IM30 and PspA-while structurally simpler-exhibit remarkable functional similarities to their eukaryotic counterparts and play essential roles in membrane remodeling and deformation, particularly under environmental stress. However, the precise mechanisms driving these biological processes remain unclear. This review explores their structural dynamics, membrane-binding behavior, and remodeling activities. Emerging <i>in vitro</i> evidence suggests that PspA and IM30 assemble into high-molecular-weight oligomeric rings and filamentous structures, facilitating membrane interactions and remodeling. In contrast to eukaryotic ESCRT-III, which requires accessory proteins to form functional remodeling complexes, bacterial ESCRT-III proteins are capable of remodeling membranes autonomously. These activities drive a variety of structural transformations, including membrane curvature, elongation, protrusion, double-membrane vesicles (DMVs) formation, and fusion. By integrating recent findings, this review provides a comprehensive overview of current knowledge and highlights key directions for future research into the mechanisms and physiological roles of bacterial ESCRT-III.