Contact sites

Eig. 2. Schematic representation of the possible fate of a chemical absorbed from a primary contact site. 

A synapse is a contact site between two neurones, where information is communicated from the axon of one neurone (the presynaptic) to the cell body, the dendrites or the axon of the second neurone (the postsynaptic). In most synapses, the information is communicated chemically ... 

Delaunay, J. Dhermy, D. (1993). Mutations involving the spectrin heterodimer contact site Clinical expression and alterations in specific function. Sem. Hematol. 30, 21-33. 

While it has been known for many years that the N-terminal presequence is sufficient to promote mitochondrial targeting and assembly, the subsequent interaction of the precursor molecule with the outer mitochondrial membrane and the uptake of the protein is still an area of active research. There seems little doubt, however, that there are proteins on the outer mitochondrial membrane which are required for the import process. The function of these proteins is uncertain, but they may act as receptors with the subsequent transfer through the membrane at proteinous pores located at contact sites between the inner and outer membranes. Several proteins have been identified which seem to play an important role as either receptor proteins or part of the import channel (Pfanner et al., 1991). Again, not all proteins seem to depend on this mechanism. Cytochrome c, which is loosely associated with the outer aspect of the inner mitochondrial membrane, can cross... 

According to Mata et al, [309], solubilization in Ci2Eg solution unmasked the inhibitory effect of several antibodies (B/3D6, Y/1F4, Y/2EG, Y/3G6, B/4H3, A/4H3 and I/2H7) on the Ca -ATPase, They suggested that these antibodies bind to protein-protein contact sites opened by the dissociation of ATPase oligomers, thus causing inhibition. Alternatively, the binding of antibody to the solubilized ATPase may promote its folding into a conformation that is unfavorable for enzymatic activity. 

Organophosphate Ester Hydraulic Fluids. Repeated application of a patch treated with 0.2 pL of Skydrol 500B-4 for 5 weeks (3 times/week) resulted in mild cumulative erythema confined to the contact site in 14 of 53 human test subjects, beginning with the third dose during the first week. No evidence of immediate primary dermal irritation was observed (Monsanto 1980). 

Prausnitz and coworkers [91,92] developed a model which accounts for nonideal entropic effects by deriving a partition function based on a lattice model with three categories of interaction sites hydrogen bond donors, hydrogen bond acceptors, and dispersion force contact sites. A different approach was taken by Marchetti et al. [93,94] and others [95-98], who developed a mean field theory... 

Kunkel GR, Mehrabian M, Martinson HG. Contact-site cross-linking agents. Mol. Cell. Biochem. 1981 34 3-13. 

Owens, J.T., Miyake, R., Murakami, K., Chmura, A.J., Fujita, N., Ishihama, A., and Meares, C.F. (1998) Mapping the sigma(70) subunit contact sites on Escherichia coli RNA polymerase with a sigma(70)-conjugated chemical protease. Proc. Nat. Acad. Sci. USA 95, 6021-6026. 

A photoreactive nucleotide, 8-bromo-2 -deoxy-adenosine, was incorporated post-synthetically into a DNA sequence (35, Fig. 13) within the previously determined DNA contact site for the transcription factor. Upon irradiation the resulting nitrene cross-linked primarily to the 50-kDa subunit and covalently modified Lys-244. On the other hand, that amino acid residue appeared not... 

Moreau, J.-F. and Hancock, R.G.V. (1999). Faces of European copper alloy cauldrons from Quebec and Ontario contact sites. In Metals in Antiquity, ed. Young, S.M.M., Pollard, A.M., Budd, P. and Ixer, R.A., BAR International Series 792, Archaeopress, Oxford, pp. 326-340. 

The general chemistry used in this approach involves the combination of a limited amount of an amine-terminated dendrimer core reagent with an excess of carboxylic acid terminated dendrimer shell reagent [31]. These two charge differentiated species are allowed to self-assemble into the electrostatically driven supramolecular core-shell tecto(dendrimer) architecture. After equilibration, covalent bond formation at these charge neutralized dendrimer contact sites is induced with carbodiimide reagents (Scheme 1). 

Figure 1. Control of mitochondrial biogenesis by the nuclear genome. Most mitochondrial proteins, including cytochrome c, are nuclear gene products which are subsequently imported into mitochondria. Similarly, most enzymes involved in synthesis of mitochondrial phosphoplipids are encoded in the nuclear genome. Being located in the endoplasmatic reticulum, they synthesize phosphatidylcholine (PtdCho), phosphatidylserine (PtdSer), phosphatidylglycerol (PG) and phosphatidylinositol (Ptdins). The phospholipids are transferred to the outer membrane. The imported lipids then move into the inner membrane at contact sites. Mitochondria then diversify phospholipids. They decarboxylate phosphatidylserine to phosphatidylethanolamine (PtdEtN), but the main reaction is the conversion of imported phosphatidylglycerol to cardiolipin (CL). Cardiolipins localize mainly in the outer leaflet of the inner membrane.

Since the enzymes involved in PS synthesis are located in ER or MAM, and PSD is exclusively located at the inner mitochondrial membrane, the conversion of PS to PE by PSD has been used as an indicator of PS translocation into the inner mitochondrial membrane (Dennis and Kennedy, 1972 Voelker, 1990). Recent studies have shown that the transport of newly synthesized PS to the outer mitochondrial membrane requires no cytosolic proteins and is probably mediated by direct contact region between MAM and mitochondria (Voelker, 1989 Voelker, 1993 Shiano et al., 1995). It is also suggested that the translocation of PS from the outer to iimer mitochondrial membrane occurs through the contact sites where the two mitochondrial membranes are closely apposed and linked in a stable manner, since agents that dismpt the contact sites such as 1,4-dinitrophenol and adriamycin inhibit the PS transport (Hovius et al., 1992 Voelker, 1991). 

ArdaU, D., Lerme, F., and Louisot P., 1991, Involvement of contact sites in phosphatidyl-serine import into hver mitochondria. 7. Biol. Chem., 266 7978-7981. 

Contact site of the medical institution in case of health damage... 

FAK Regulation cell adhesion at cell-matrix and cell-cell contact sites (WIO)... 

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