Transporters cell-specific

These data confirmed the generally accepted mechanism for the energy supply process that involves yolk lipoproteins. Moreover, the results proved the value of NDs as biomolecular nanocarriers for intercellular transport, cell-specific targeting, and long-term imaging applications in vivo. 

Microtubules are universally present in eukaryotes from protozoa to the cells of higher animals and plants (Porter, 1966 Hardham and Gunning, 1978 Lloyd, 1987), but they are absent in mammalian erythrocytes and in prokaryotes. Microtubules participate in a number of cellular functions including the maintenance of cell shape and polarity, mitosis, cytokinesis, the positioning of organelles, intracellular transport to specific domains, axoplasmic transport, and cell locomotion. The diversity of microtubule fimctions suggests that not all microtubules are identical and that different classes of microtubules are present in different cell types or are localized in distinct domains in the same cell type (Ginzburg et al., 1989). 

Allikmets, R, Singh, N, Sun, H, Shroyer, NE, Hutchinson, A, Chidambaram, A, Gerrard, B et al. 1997. A photoreceptor cell-specific ATP-binding transporter gene (ABCR) is mutated in recessive Stargardt macular dystrophy. Nat Genet 15, 236-246. 

Tomita, S., et. al., T cell-specific disruption of the aryl hydrocarbon receptor nuclear transporter (Amt) gene causes resistance to 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced thymic involution, J. Immunol., 171, 4113, 2003. 

Targeting of Intestinal Transporters 6.2.22. Targeting of Cell-Specific Transporters... 

Fig. 6.8. Schematic representation of a selective delivery obtained by targeting a cell-specific transporter, a) The drug itself does not permeate passively into cells and is not a substrate of the transporter, b) The prodrug does not permeate passively into cells but is a substrate of the transporter. An additional condition of success is for the prodrug to undergo intracellular... 

Rohaceir, a closed-cell PMI foam developed by Rohm of Germany to be used as cores in lightweight sandwich composites for transport, has specific advantages ... 

Choy et al. have also intercalated biological macromolecules such as DNA, ATP and nucleosides into Mg/Al-NOs LDHs [189,190,194,195], where the host lattice may protect relatively delicate biomolecules from degradation and also aid their transport to specific targets within the body, and hence the intercalation reactions lead to the formation of novel bioinorganic nanohybrids with potential practical significance, such as new DNA reservoirs or carriers for the delivery of genetic material to cells [189]. 

The transport from nucleus to cytoplasm is accompanied by modification at the 5 - and 3 -end of the pre-RNA, as well as by processing (splicing) of the primary transcript. The 3 -end modifications and sphcing decide which information contained in the primary transcript is made available for protein biosynthesis. The information content of the processed mRNA can be specifically influenced by these processes. This has an important impact on the tissue- and cell-specific protein expression. 3 -modification and splicing are tightly coupled to extranuclear transport. Interventions in the transport process are another possibihty for a regulation at the post-transcriptional level. 

ATP is a crucial intermediate for cells to maintain normal activities without a minimum level, the cell will die as systems will fail. ATP is the energy currency of the cell and is required for the synthesis of many substances such as macromolecules for structural and functional purposes, which the cell needs, but also for processes such as cell division, maintenance of the correct ionic balance, muscular and electrical activity, ciliary movement, membrane transporters, and specific ion channels. 

Most Solutes Are Transported by Specific Carriers materials inside the cell. But the plasma membrane is not... 

Biological membranes contain proteins that act as specific transporters of small molecules into and out of the cell. Most solutes are transported by specific carriers that are invariably proteins. 

Figure 12.8 Model for general and cell-specific plasmid nuclear import. (A) SV40 enhancer-mediated nuclear import. Because the transcription factors bound by this DNA sequence are ubiquitously expressed, SV40 DNA localizes to the nuclei of all cell types (see Table 12.1). (B) Smooth muscle-specific plasmid nuclear import. Smooth muscle-specific transcription factors, including SRF among others, can bind to their target sites within the SMGA promoter carried on a plasmid and serve to transport the DNA to the nucleus via interactions with the NLS-mediated protein import machinery. Since these factors are not expressed in other cell types, no nuclear import will occur in non-smooth muscle cells.

Tsubata, T., and M. Reth. 1990. The products of pre-B cell-specific genes (lambda 5 and VpreB) and the immunoglobulin mu chain form a complex that is transported onto the cell surface. J. Exp. Med. 172 973-976. 

Three types of transport mechanisms for bicarbonate have been identified (a) an electroneutral Na+ dependent Cr/HCO cotransporter (b) an electroneutral, Na+ independent Cl /HCO cotransporter and (c) an electrogenic NaVHCOj n (n>l) cotransporter. Unlike the Na+/H+ exchanger which is ubiquitous, bicarbonate transport mechanisms are expressed in a cell specific manner. In most cell types, however, the Na+/H+ exchanger coexists with one or several bicarbonate transport systems. As a consequence, pHi regulation can be achieved by various means in different cell types. 

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