Sites of Membranes

While recent attention has been largely on proteins, it should be borne in mind that membrane fusion ultimately involves the merger of phospholipid bilayers. However, little is known about the specific membrane lipid requirements. When membranes fuse, energetically unfavorable transition states are generated that may require specific lipids and lipid domains for stabilization. Although there is some evidence for a specific influence of lipids on exocytosis, it is still unclear whether specific lipid metabolites are needed or even generated at the site of membrane merger. 

R. J. Bloch, M. Velez, J. Krikorian, and D. Axelrod, Microfilaments and actin-associated proteins at sites of membrane-substrate attachment within acetylcholine receptor clusters, Exp. Cell Res. 182, 583-596 (1989). 

This interconnected network of membrane vesicles is divided into two distinct parts. The rough endoplasmic reticulum (RER), which is studded with ribosomes, is the site of membrane and secretory protein biosynthesis and their post-translational modification. The smooth endoplasmic reticulum (SER) is involved in phospholipid biosynthesis and in the detoxification of toxic compounds. 

All the materials mentioned above are discussed in the current chapter. If possible, SI units are applied for the data— the reader may find a useful table for conversion of units in Ref. [16]. Many good review papers and chapters in books on membranes for gas applications have been published recent years only a few are referred to here [17-19]. A rich source of information on membrane materials and gas separation may also be found on the Web site of membrane producers and research institutes. One example is MTR [20]. 

These fusion events all have a common feature of increase in surface energy at the site of membrane fusion. In this sense, these membrane fusions can be explained by the theoretical interpretation presented here and it will... 

It is thought that the amino-terminal surface-exposed regions of the complex are sites of membrane adhesion that cause thylakoid stacking (5). This is consistent with the three-dimensional structure proposed by Kuhlbrandt on the basis of electron microscopy of two-dimensional crystals (6). This structure has three-fold rotational symmetry and a platform at one surface that could provide for interaction with a neighbouring platform through van der Waals forces. 

Specific Interactions of Xanthene Dyes with Nucleotide-Binding Sites of Membrane Energy-Transducing Enzymes and Carriers... 

A two-component bilayer and isotropic NMR spectrum from a membrane (usually a natural membrane) has been interpreted in terms of a major bilayer structure encompassing a much smaller (<5%) population of inverted micelles. Although not the only explanation, the interpretation has many functionally attractive features (enhanced permeability, sites of membrane fusion, flip-flop regions, etc). Such isotropic spectral components are often produced by proteins interacting with the surface of lipid bilayers. The identity of the lipid type, in a mixed lipid membrane, which exists in this isotropic environment, can be determined using MAS NMR methods. 

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