Researchers have made groundbreaking discoveries in the field of nanoscale endocytic processes. By using coarse-grained molecular dynamics simulations, they have uncovered the morphological responses of nanovesicles when they come into contact with small liquid droplets.
The results of the simulations have identified different pathways of endocytosis, leading to a deeper understanding of this complex process.
The study found that the endocytic pathways are primarily dependent on two key parameters: the transbilayer stress asymmetry of the membrane and the line tension of the contact line between membrane and droplet. Furthermore, the researchers utilized the general isoperimetric inequality from differential geometry to show that complete engulfment of the droplet is only possible for droplets that do not exceed a certain maximal volume. This cutting-edge research has the potential to revolutionize the field of nanoscale endocytosis.
Bullet point summary:
- Researchers studied the morphological responses of nanovesicles and liquid droplets.
- Different pathways of endocytosis were identified.
- Complete engulfment of droplets was shown to be possible only for small droplets.
- Two key parameters were determined to control endocytic pathways:
- Transbilayer stress asymmetry of the membrane
- Line tension of the contact line between membrane and droplet
The researchers used coarse-grained molecular dynamics simulations to study the morphological responses of nanovesicles when they come into contact with small liquid droplets. They found that the lipid numbers N ol and N il used to assemble the outer and inner leaflets determine the leaflet tensions and the stress asymmetry between the two leaflets. The study demonstrated that the endocytic pathways at the nanoscale are dependent primarily on the two key parameters: the transbilayer stress asymmetry of the membrane and the line tension of the contact line between membrane and droplet. To determine the bilayer tensions and line tension, the researchers considered a partially engulfed droplet and applied a previously developed methodology. The results showed that complete engulfment of the droplet is only possible for sufficiently small droplets that do not exceed a certain maximal droplet volume.
Outcomes:
- Researchers used coarse-grained molecular dynamics simulations to investigate the morphological responses of nanovesicles when they come into contact with small liquid droplets.
- Different pathways of endocytosis were identified based on the resulting vesicle-droplet morphology.
- The study showed that complete engulfment of the droplet is only possible for sufficiently small droplets.
- Two key parameters, the transbilayer stress asymmetry of the membrane and the line tension of the contact line between membrane and droplet, were determined to control the endocytic pathways.
Different pathways for engulfment and endocytosis of liquid droplets by nanovesicles
Ghosh; Satarifard; Lipowsky
Full-text link: https://doi.org/10.1038/s41467-023-35847-z
What this paper is about
- Each bilayer consists of two leaflets, with N ol lipids in the outer leaflet and N il lipids in the inner leaflet.
- Inspection of shows that the lipid numbers N ol and N il = 10,100 N ol used to assemble the outer and inner leaflets determine the leaflet tensions ol and il and thus the stress asymmetry between the two leaflets.
- Nanovesicles formed by a tensionless bilayer with a stretched outer leaflet and a compressed inner one are then obtained for N ol < 5963 and N il > 4137.
What you can learn
- Interfacial tension, bilayer tension of the membrane segment, and bilayer tension of the membrane segment as functions of the lipid number N ol in the outer bilayer leaflet.
- Which pathway is taken depends on the droplet size and on two key parameters: the transbilayer stress asymmetry between the two leaflets of the bilayer membrane in the absence of a droplet, as controlled by the outer lipid number N ol during the initial assembly of the vesicle; and the line tension of the contact line between droplet and vesicle membrane.
- As we reshuffle lipids from the inner to the outer leaflet, the vesicle membrane prefers to attain a more positive mean curvature which implies an increased bilayer tension for the segment in contact with the droplet and a reduced bilayer tension for the segment not exposed to the droplet.
- Likewise, the inner leaflet of the segment has surface area A and encloses the combined volume V. The corresponding isoperimetric inequality now has the form A 36 1=3 V. V 2=3 !
- To obtain the bilayer tensions and of the two membrane segments as well as the interfacial tension of the liquid-liquid interface, we consider a partially engulfed droplet, forming an axisymmetric geometry with the nanovesicle as in, and apply the methodology previously developed in ref.
- P yy are displayed in as functions of the two coordinates y and r. In each case, the volume of the nanovesicle has been adjusted.
Q: What is the paper about?
A: The paper discusses the morphological responses of nanovesicles when they come into contact with small liquid droplets and the endocytic pathways that result from this interaction.
Q: What are the key parameters affecting the endocytic pathways?
A: The endocytic pathways are primarily dependent on two key parameters: the transbilayer stress asymmetry of the membrane and the line tension of the contact line between membrane and droplet.
Q: What can you learn from the paper?
A: You can learn about the relationship between the lipid number Nol in the outer leaflet of a bilayer and the bilayer tensions, interfacial tension, and the pathways of endocytosis taken by a droplet.
Q: What is the general isoperimetric inequality from differential geometry used for in the paper?
A: The general isoperimetric inequality from differential geometry is used to show that complete engulfment of a droplet by a nanovesicle is only possible for droplets that do not exceed a certain maximal droplet volume.
