Budding and Fission of Membrane Vesicles: A Mini Review

Abstract

In this mini-review, a brief historical survey of the mechanisms which determine the shapes of liposomes and cells and the budding and fission of their membrane is presented. Special attention is given to the role of orientational ordering of membrane components in thin membrane necks which connect the membrane buds (daughter vesicles) to the parent membrane. It is indicated that topological anti-defects in membrane necks may induce the rupture of the neck and the fission of the membrane daughter vesicles.

On the Role of Curved Membrane Nanodomains and Passive and Active Skeleton Forces in the Determination of Cell Shape and Membrane Budding

“…The theoretically predicted shape in Figure 14 a is calculated in the absence of the active force of NMIIA nanodomains and may partially correspond to the situations in RBCs where the protrusion is growing in the region in which the local disruption of the membrane skeleton and the membrane bilayer interactions appears or the skeleton is detached from the protrusion [ 160 , 167 ]. In such cases, the inward membrane protrusion does not contain membrane skeleton [ 168 ].…”

“…One observes that the nanodomain cluster size distribution has two distinct peaks corresponding to spheroidal (smaller) and necklace-like (larger) aggregates of nanodomains ( Figure 14 a). The nanodomains aggregate into curved membrane protrusions or buds as a consequence of non-zero (negative) intrinsic curvature of nanodomains and high enough attractive interaction energy between nanodomains/inclusions [ 168 ]. Note that there are no isotropic nanodomains in a highly curved neck region of the invagination (denoted by red arrow in Figure 14 a).…”

“…The membrane curvature in the neck region is anisotropic ( ) and therefore not favorable for highly curved isotropic ( ) nanodomains/inclusions. For long term stabilization of the neck connecting the bud and the parent membrane, one would have to take into account in MC simulations also the effect of anisotropic nanodomains [ 15 , 81 , 89 , 168 , 169 ]. Anisotropic saddle-like nanodomains would in this case assemble in the neck region and stabilize the neck [ 170 ].…”

“…Note that large invaginations can be separated from the parent cell due to local frustrations in orientational in-plane ordering of membrane constituents in highly curved membrane parts such as membrane necks connecting the invagination and the parent cell [ 168 , 171 ]. Highly curved membrane regions such as membrane necks are likely to host topological defects, which are a source of large elastic penalties [ 168 , 171 ]. Invaginated stomatocyte neck region is a relatively small surface, which can host up to four topological defects.…”

Minimizing isotropic and deviatoric membrane energy – An unifying formation mechanism of different cellular membrane nanovesicle types

“…Correspondence between the observed and the calculated shapes was reported in numerous studies that elaborated various phase diagrams of possible shapes (see for example an extensive review of early work by U. Seifert (1997) [14]). Also inhomogeneities of the membrane composition were taken into account in theoretical descriptions and observed in experimental systems [15][16][17][18][19][20].…”