Membrane inward/outward budding and transition pathway induced by the asymmetric solutions

Zhou, Qi; Peng, Yuxuan; Wang, Ping; 江, 鐘偉; Zhao, Xin-Jun; Zhu, Tao

doi:10.1016/j.colsurfa.2023.132111

Cited by 1 publication

(2 citation statements)

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“…Moreover, because the buds produced invariably extend toward the interior lumen of the mother GUVs, the generated spontaneous curvature, presumably because of the asymmetry induced by the differences in the dissolved solutes, must also be negative. A recent study, however, suggests that the lipid bilayers experiencing glucose–sucrose asymmetry tend to bend in the direction of the glucose-laden solution, which in our case would produce outward budding. In our case, it is clear that both the volume reduction and spontaneous curvature play a role.…”

Section: Resultscontrasting

confidence: 61%

“…The most general unifying framework for understanding osmotically induced membrane invaginations invokes reduced volume, such as occurs during osmotic deflation, and spontaneous curvature, which arises because of imposed solution asymmetry surrounding the membrane. , The osmotic deflation implies that the GUVs lose intravesicular volume in the fixed membrane area. As a consequence, the newly created excess membrane area undergoes reorganization to minimize the free energy .…”

Section: Resultsmentioning

confidence: 99%

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Intravesicular Solute Delivery and Surface Area Regulation in Giant Unilamellar Vesicles Driven by Cycles of Osmotic Stresses

Sambre,

Ho,

Parikh

2024

J. Am. Chem. Soc.

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Phospholipid bilayers are dynamic cellular components that undergo constant changes in their topology, facilitating a broad diversity of physiological functions including endo-and exocytosis, cell division, and intracellular trafficking. These shape transformations consume energy, supplied invariably by the activity of proteins. Here, we show that cycles of oppositely directed osmotic stresses�unassisted by any protein activity�can induce welldefined remodeling of giant unilamellar vesicles, minimally recapitulating the phenomenologies of surface area homeostasis and macropinocytosis. We find that a stress cycle consisting of deflationary hypertonic stress followed by an inflationary hypotonic one prompts an elaborate sequence of membrane shape changes ultimately transporting molecular cargo from the outside into the intravesicular milieu. The initial osmotic deflation produces microscopic spherical invaginations. During the subsequent inflation, the first subpopulation contributes area to the swelling membrane, thereby providing a means for surface area regulation and tensional homeostasis. The second subpopulation vesiculates into the lumens of the mother vesicles, producing pinocytic vesicles. Remarkably, the gradients of solute concentrations between the GUV and the daughter pinocytic vesicles create cascades of water current, inducing pulsatory transient poration that enable solute exchange between the buds and the GUV interior. This results in an efficient water-flux-mediated delivery of molecular cargo across the membrane boundary. Our findings suggest a primitive physical mechanism for communication and transport across protocellular compartments driven only by osmotic stresses. They also suggest plausible physical routes for intravesicular, and possibly intracellular, delivery of ions, solutes, and molecular cargo stimulated simply by cycles of osmotic currents of water.

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Section: Resultscontrasting

confidence: 61%