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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 series of snapshots of the birthing process observed in the binary vesicle composed of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE)/DPPC = 3/7. The birthing cycle consists of four steps: (1) sphere to stomatocyte deformation; (2) formation of the inclusion vesicle; (3) birthing of the daughter vesicle through a pore; and (4) recovery of the spherical vesicle by closing the pore. The green and red pathways show the birthing of the second daughter vesicle and the granddaughter vesicle, respectively. The scale bar indicates 5 μm.
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life-05-00651-f020: A series of snapshots of the birthing process observed in the binary vesicle composed of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE)/DPPC = 3/7. The birthing cycle consists of four steps: (1) sphere to stomatocyte deformation; (2) formation of the inclusion vesicle; (3) birthing of the daughter vesicle through a pore; and (4) recovery of the spherical vesicle by closing the pore. The green and red pathways show the birthing of the second daughter vesicle and the granddaughter vesicle, respectively. The scale bar indicates 5 μm.

Mentions: A unique feature of the model system is that it can reproduce the birthing and the budding pathways. The observed birthing pathway in the binary GUVs with a composition of DLPE/DPPC = 3/7 is shown in Figure 20. The experiment was started from a spherical vesicle at 35 °C, below the Tm of DPPC (Step 1). By increasing the temperature above the Tm (42 °C), chain melting took place, which produced the excess area. Using the excess area, the spherical GUV deformed to a stomatocyte shape (Step 2). As time elapsed, the stomatocyte vesicle spontaneously formed an inclusion vesicle inside the mother vesicle by pinching off the invagination neck (Step 3). When the temperature was decreased below the Tm of DPPC (35 °C), the surface area of the mother vesicle decreased due to chain ordering. This change resulted in an increase in the membrane tension of the mother vesicle. To release the tension, the mother vesicle formed a single pore, and the inclusion vesicle was discharged through the pore, i.e., birthing of the daughter vesicle (Step 4). After the birthing, the pore was immediately resealed due to the line tension, and the mother GUV recovered a spherical shape, although the resulting GUV had a smaller size as the original GUV. Interestingly, when the temperature was again increased above the Tm, the recovered spherical mother GUVs formed inclusion vesicles, and then, a second daughter vesicle was born when the temperature decreased below the Tm (Figure 20, green pathway). In addition, the daughter vesicle followed the same birthing pathway and produced granddaughter vesicles (Figure 20, red pathway). This result indicates that the birthing ability is maintained in the next generation (sometimes fourth- or fifth-generation vesicles).


From vesicles to protocells: the roles of amphiphilic molecules.

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

A series of snapshots of the birthing process observed in the binary vesicle composed of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE)/DPPC = 3/7. The birthing cycle consists of four steps: (1) sphere to stomatocyte deformation; (2) formation of the inclusion vesicle; (3) birthing of the daughter vesicle through a pore; and (4) recovery of the spherical vesicle by closing the pore. The green and red pathways show the birthing of the second daughter vesicle and the granddaughter vesicle, respectively. The scale bar indicates 5 μm.
© Copyright Policy
Related In: Results  -  Collection

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

life-05-00651-f020: A series of snapshots of the birthing process observed in the binary vesicle composed of 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE)/DPPC = 3/7. The birthing cycle consists of four steps: (1) sphere to stomatocyte deformation; (2) formation of the inclusion vesicle; (3) birthing of the daughter vesicle through a pore; and (4) recovery of the spherical vesicle by closing the pore. The green and red pathways show the birthing of the second daughter vesicle and the granddaughter vesicle, respectively. The scale bar indicates 5 μm.
Mentions: A unique feature of the model system is that it can reproduce the birthing and the budding pathways. The observed birthing pathway in the binary GUVs with a composition of DLPE/DPPC = 3/7 is shown in Figure 20. The experiment was started from a spherical vesicle at 35 °C, below the Tm of DPPC (Step 1). By increasing the temperature above the Tm (42 °C), chain melting took place, which produced the excess area. Using the excess area, the spherical GUV deformed to a stomatocyte shape (Step 2). As time elapsed, the stomatocyte vesicle spontaneously formed an inclusion vesicle inside the mother vesicle by pinching off the invagination neck (Step 3). When the temperature was decreased below the Tm of DPPC (35 °C), the surface area of the mother vesicle decreased due to chain ordering. This change resulted in an increase in the membrane tension of the mother vesicle. To release the tension, the mother vesicle formed a single pore, and the inclusion vesicle was discharged through the pore, i.e., birthing of the daughter vesicle (Step 4). After the birthing, the pore was immediately resealed due to the line tension, and the mother GUV recovered a spherical shape, although the resulting GUV had a smaller size as the original GUV. Interestingly, when the temperature was again increased above the Tm, the recovered spherical mother GUVs formed inclusion vesicles, and then, a second daughter vesicle was born when the temperature decreased below the Tm (Figure 20, green pathway). In addition, the daughter vesicle followed the same birthing pathway and produced granddaughter vesicles (Figure 20, red pathway). This result indicates that the birthing ability is maintained in the next generation (sometimes fourth- or fifth-generation vesicles).

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