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From vesicles to protocells: the roles of amphiphilic molecules.

Sakuma Y, Imai M - Life (Basel) (2015)

Bottom Line: It is very challenging to construct protocells from molecular assemblies.Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation.This achievement will elucidate the pathway from molecular assembly to cellular life.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan. sakuma@bio.phys.tohoku.ac.jp.

ABSTRACT
It is very challenging to construct protocells from molecular assemblies. An important step in this challenge is the achievement of vesicle dynamics that are relevant to cellular functions, such as membrane trafficking and self-reproduction, using amphiphilic molecules. Soft matter physics will play an important role in the development of vesicles that have these functions. Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation. This achievement will elucidate the pathway from molecular assembly to cellular life.

No MeSH data available.


Related in: MedlinePlus

(a) Budding of membrane domain β embedded in the membrane matrix α (taken from [66]); budding (b) and complete budding (c) of phase separated vesicle composed of sphingomyelin, DOPC and cholesterol. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. Scale bars, 5 μm (taken from [68]).
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life-05-00651-f019: (a) Budding of membrane domain β embedded in the membrane matrix α (taken from [66]); budding (b) and complete budding (c) of phase separated vesicle composed of sphingomyelin, DOPC and cholesterol. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. Scale bars, 5 μm (taken from [68]).

Mentions: A simple route to produce budding and fission events on the vesicle is to use the phase separation of the binary vesicle [66,67,68]. Through phase separation, domains having different lipid compositions appear on the vesicle (β phase in the α phase: Figure 19a), which results in a line tension at the domain boundary. A competition between the bending energy and the line energy causes budding. When the bending energy governs the system, the membrane prefers a flat geometry (Figure 19a-1). In contrast, when the line energy is dominant, the vesicle forms a bud to decrease the edge length of the domain, and finally, the bud domain forms a separated vesicle (complete budding), where the line energy disappears (Figure 19a-2,a-3). The budding of a phase separated vesicle is shown in Figure 19b,c. The vesicle is composed of sphingomyelin, DOPC and cholesterol. Through phase separation, sphingomyelin and cholesterol enrich in a liquid phase with short-range order (Lo), and DOPC prefers a disordered liquid (Ld) phase. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. In this budding mechanism, however, the composition of the daughter vesicle is different from that of the mother vesicle, i.e., it is not recursive.


From vesicles to protocells: the roles of amphiphilic molecules.

Sakuma Y, Imai M - Life (Basel) (2015)

(a) Budding of membrane domain β embedded in the membrane matrix α (taken from [66]); budding (b) and complete budding (c) of phase separated vesicle composed of sphingomyelin, DOPC and cholesterol. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. Scale bars, 5 μm (taken from [68]).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390873&req=5

life-05-00651-f019: (a) Budding of membrane domain β embedded in the membrane matrix α (taken from [66]); budding (b) and complete budding (c) of phase separated vesicle composed of sphingomyelin, DOPC and cholesterol. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. Scale bars, 5 μm (taken from [68]).
Mentions: A simple route to produce budding and fission events on the vesicle is to use the phase separation of the binary vesicle [66,67,68]. Through phase separation, domains having different lipid compositions appear on the vesicle (β phase in the α phase: Figure 19a), which results in a line tension at the domain boundary. A competition between the bending energy and the line energy causes budding. When the bending energy governs the system, the membrane prefers a flat geometry (Figure 19a-1). In contrast, when the line energy is dominant, the vesicle forms a bud to decrease the edge length of the domain, and finally, the bud domain forms a separated vesicle (complete budding), where the line energy disappears (Figure 19a-2,a-3). The budding of a phase separated vesicle is shown in Figure 19b,c. The vesicle is composed of sphingomyelin, DOPC and cholesterol. Through phase separation, sphingomyelin and cholesterol enrich in a liquid phase with short-range order (Lo), and DOPC prefers a disordered liquid (Ld) phase. The phase separation was visualized using perylene (blue) in the Lo phases and rhodamine-DPPE (red) in the Ld phases. In this budding mechanism, however, the composition of the daughter vesicle is different from that of the mother vesicle, i.e., it is not recursive.

Bottom Line: It is very challenging to construct protocells from molecular assemblies.Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation.This achievement will elucidate the pathway from molecular assembly to cellular life.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Tohoku University, Aoba, Sendai 980-8578, Japan. sakuma@bio.phys.tohoku.ac.jp.

ABSTRACT
It is very challenging to construct protocells from molecular assemblies. An important step in this challenge is the achievement of vesicle dynamics that are relevant to cellular functions, such as membrane trafficking and self-reproduction, using amphiphilic molecules. Soft matter physics will play an important role in the development of vesicles that have these functions. Here, we show that simple binary phospholipid vesicles have the potential to reproduce the relevant functions of adhesion, pore formation and self-reproduction of vesicles, by coupling the lipid geometries (spontaneous curvatures) and the phase separation. This achievement will elucidate the pathway from molecular assembly to cellular life.

No MeSH data available.


Related in: MedlinePlus