What Are the Various Mechanisms of Plasma Membrane Domain Formation?

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What are the various mechanisms of plasma membrane domain formation? The plasma membrane is vital to existence of the cell. It is the boundary dividing and protecting the intracellular components from the extracellular environment. The membrane is selectively permeable, allowing it control over ions and other molecules that may be transported in or out of the cell. This actively maintains the essential differences between the inside and outside environment. In addition it acts as an attachment area for the intracellular cytoskeleton and the cell wall. (Alberts et al., 2008) The basic matrix of the plasma membrane is made of the lipid bilayer, formed by amphipathic polar phospholipids, with hydrophobic and hydrophilic parts. The predisposition of the hydrophilic portions to interrelate with their external aqueous environments and themselves. Therefore the inclination of the hydrophobic portions to stick together, is the origin of spontaneous membranes formation. In addition to the bilayer, there is a large variety of lipid and protein species involved in membrane composition and structure. Lipids differ in headgroups and fatty acid tail length, and proteins differ in their amino acid sequences and properties. The membrane lipids and proteins create an asymmetric formation so their concentrations differ on each membrane leaflet. They are spread across the membrane with their hydrophilic parts facing outward and hydrophobic parts facing inward. (Van Meer et al., 2008) Type of Lipid Species. | Charge on the Lipid Species | Distribution on Inner or Outer Membrane Leaflet | Phosphatidylinositides | Negative | Inner | Phosphatidylserines | Negative | Inner | Phosphatidylcholines | Positive | Outer | Sphinogolipids | Positive | Outer | Table 1 summarizes how a factor for lipid species distribution on each membrane leaflet can be the charge on the lipid

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