Coupling of the fusion and budding of giant phospholipid vesicles containing macromolecules

Abstract

Mechanisms that enabled primitive cell membranes to self-reproduce have been discussed based on the physicochemical properties of fatty acids; however, there must be a transition to modern cell membranes composed of phospholipids [Budin I, Szostak JW (2011) Proc Natl Acad Sci USA 108:5249–5254]. Thus, a growth-division mechanism of membranes that does not depend on the chemical nature of amphiphilic molecules must have existed. Here, we show that giant unilamellar vesicles composed of phospholipids can undergo the coupled process of fusion and budding transformation, which mimics cell growth and division. After gaining excess membrane by electrofusion, giant vesicles spontaneously transform into the budded shape only when they contain macromolecules (polymers) inside their aqueous core. This process is a result of the vesicle maximizing the translational entropy of the encapsulated polymers (depletion volume effect). Because the cell is a lipid membrane bag containing highly concentrated biopolymers, this coupling process that is induced by physical and nonspecific interactions may have a general importance in the self-reproduction of the early cellular compartments.

Monodisperse Uni- and Multicompartment Liposomes

“…9,10 Cell-sized liposomes that encapsulate biomolecules and incorporate biological functions provide a versatile mimic of certain aspects of living cells, as exemplified by work showing RNA replication, [11][12][13] in vitro transcription and translation of gene networks, 6,14-16 and organization of cell division machinery in liposomes. [17][18][19][20][21][22][23][24] …”

Physico-chemical interactions between compartment-forming lipids and other prebiotically relevant biomolecules

“…Budin et al [16], Hanczyc et al [17] and Terasawa et al [18] among others have addressed possible ways for primitive vesicles to bud and divide. In particular, Terasawa et al showed how biopolymers could favor the growth and division of vesicles by budding, which is a process comparable to the division mechanism in L-form bacteria [19].…”

Molecular Building Blocks and Their Architecture in Biologically/Environmentally Compatible Soft Matter Chemical Machinery

“…These studies have focused on gene expression and metabolic reaction networks in GVs and the control of deformations of GV membranes. 87 . This trend shows the acceleration of the construction of protocell models that exhibit adaptability to open systems and their applications.…”