membránfluentia

Membránfluentia is a term used in cell biology to describe a proposed mode of membrane remodeling in which lipid and protein constituents reorganize and redistribute across the plane of the bilayer in a fluid, continuous manner. In this view, membranes can exhibit rapid, localized remodeling that moves components laterally without the formation of discrete vesicles or classical fusion events.

Proponents describe a mechanism in which high lateral mobility of certain lipids, coupled with networks of curvature-sensing and curvature-inducing proteins, creates transient pathways for material exchange within the bilayer. The cytoskeleton, particularly cortical actin and associated BAR-domain proteins, is thought to regulate these flows by modulating tension and curvature. Energetics remain debated, but local lipid phase behavior, protein crowding, and actomyosin-generated forces are proposed to drive the process.

Evidence for membránfluentia is presently indirect and largely theoretical. Some super-resolution and live-cell imaging studies report rapid, non-vesicular redistribution of membrane markers and proteins that are not easily reconciled with vesicle traffic alone. Critics argue that observations may reflect rapid vesicle turnover or imaging artifacts. As a result, membránfluentia remains a contested concept and is not part of standard models of membrane trafficking.

If validated, membránfluentia could complement or modify current views of endo/exocytosis, organelle shaping, and signaling, with potential implications for understanding mechanical adaptation and the design of synthetic membranes. The term is variably used in speculative discussions and is not universally standardized across the literature.