Membrane folds

At a more molecular level, the influences of the composition of the membrane domains, which are characteristic of a polarized cell, on diffusion are not specifically defined. These compositional effects include the differential distribution of molecular charges in the membrane domains and between the leaflets of the membrane lipid bilayer (Fig. 3). The membrane domains often have physical differences in surface area, especially in the surface area that is accessible for participation in transport. For example, the surface area in some cells is increased by the presence of membrane folds such as microvilli (see Figs. 2 and 6). The membrane domains also have differences in metabolic selectivity and capacity as well as in active transport due to the asymmetrical distribution of receptors and transporters. 

Chazotte, B., and Hackenbrock, C.R. (1991) Lateral diffusion of redox components in the mitochondrial inner membrane is unaffected by inner membrane folding and matrix density./. Biol. Chem. 266, 5973. 

Norlen, L., Skin barrier formation the membrane folding model, J. Invest. Dermatol., 117, 823, 2001. 

Tectiviridae—Icosahedral phages usually lacking a tail but with an internal membrane Fold P3 protein has two jelly-roll domains... 

Since the electron density distributions in the different spaces separated by the membranes are similar across the very different membrane topologies, there is little doubt that shape transformations of the membrane occur through intersection-free membrane folding. The work by G.W. Anderson and... 

The P-adrenoreceptor was the first of this type to be characterized and others seem to be similar. The structure is a single polypeptide chain spanning the membrane, folded into seven transmembrane domains and coupled to a G-protein. (See Figure 3.5.)... 

Animal viruses can infect and lyse a cell, or they can reside in the cell for a long period of time and continuously release progeny to infect nearby cells. Regardless of the outcome, viruses first must enter the cell by binding to cellular-membrane proteins. Through the natural process of endocytosis, viruses are often brought into the cell by receptor-mediated events that involve clatharin-coated pits, as shown in Figure 30.1. As the cell membrane folds around the virus, coated vesicles are formed, which then enter the cytoplasm and fuse with other intracellular vesicles called endosomes. 

How would a protein that resides in the interior of a membrane fold, compared with the water-soluble protein just discussed ... 

Two representative membrane folds are illustrated for (A) all a-helices of rhodopsin (lL9H.pdb) with seven membrane traversing a-helical segments and (B) 16-stranded 3-barrel structure of porin (2POR.pdb). 

Both electric and ultrasonic fields reduce membrane folding caused by the deposition of colloidal material over a range of operating conditions. 

The 6 subunit of both the Na,K and H,K ATPases is necessary for targeting the complex from the endoplasmic reticulum to the plasma membrane. It also stabilizes a functional form of both the gastric H,K and Na,K ATPases. The region of assodation of the two subunits helps explain this functional assodation, and this assodation is apparently vital for stable membrane folding of the a subunit. The B subunit, however, can traffic to the plasma membrane in the absence of the a subunit. 

Dural membranes fold or form a sac to form three important structures. The diaphragma sel-lae is a small fold of dura that covers the hypophyseal fossa of the sella turcica of the sphenoid,... 

---