Subcellular localization

Molecular subcellular imaging allows the visualization of small molecules in a physiological environment (cell or animal). There are a vast number of fluorescent techniques available to scientists to assist in molecular lead generation however, the scope of these technologies is beyond what can be described here. 

Even without the use of additional reporters, small-molecule imaging provides a wealth of information that can inform and facilitate the triaging of potential lead candidates. Perhaps, the most critical information obtained from these microscopy studies is the subcellular localization (and therein cell permeability) and biodistribution of the small molecule additionally, the accumulated local concentration and half-life of the probe can be determined for in vivo models [28]. The use of a second reporter, that is, labeled antibody or fluorescent protein, can demonstrate target engagement within a biological environment 

The major sites of O2 production in eukaryotic cells are chloroplasts and mitochondria, where the evolution of dioxygen and the reduction of dioxygen proceed at a high flux rate. Due to the low permeability of O2 toward membranes,22) O2 must be removed effectively at the site of its production. The production and scavenging of active species of oxygen in chloroplasts have been well elucidated.5) 

Chloroplast type of CuZn-SOD isozyme is localized in the chloroplast stroma of most plants, whereas Fe-SOD occurs in chloroplasts of Euglena, the moss Marchantia polymorpha and several species of seed plant. So far Mn-SOD has not been detected in chloroplasts in a soluble form but occurs in a thylakoid membrane-bound form.23,24) The cytosolic CuZn-SOD, which is distinguishable from the chloroplastic CuZn-SOD in terms of amino acid sequence, occurs in cell compartments other than chloroplasts and in nonphotosynthetic tissues.14) 

In mitochondria of animals, plants and fungi, Mn-SOD is localized in the matrix. In 

The existence of RACKs may explain the reported association of various PKC isozymes with cytoskeletal elements (Leach et al., 1989 Mochley-Rosen et al., 

VSM cell motility and for transmitting force between cells. 

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Subcellular localization pH Optimum Amino acids (in human) Species... 

SARA is a scaffolding protein that regulates the subcellular localization of inactivated R-Smads, potentially scaffolding the TGF-P receptor kinase to the Smad 2 substrate. Filamins are a family of actin polymerization proteins that also form scaffolds for a range of signaling proteins including SAP kinases such as MKK-4, small GTPases Rho and Ras, as well as Smad 2 and Smad 5. 

ELF, a (3-Spectrin, is a key component of TGF- 3 signaling that functions to recruit Smads to the receptor by controlling the subcellular localization of Smad 3 and Smad 4. Interestingly, ELF does not appear to interact with SARA or filamin, and in elf mutants, SARA and filamin distribution is the same as in wild-type mice. Thus, TGF- 3 signaling through R-Smad/ ELF interactions may work by way of a different mechanism than that of SARA and filamin. 

Wagner, M.C., Barylko, B., Albanesi, J.P. (1992). Tissue distribution and subcellular localization of mammalian myosin I. J. Cell Biol. 119, 163-170. 

Brooks P et al Subcellular localization of proteasomes and their regulatory complexes in mammalian cells. Biochem J 2000 346 155. 

The estrogens are a family of hormones synthesized in a variety of tissues. 17P-Estradiol is the primary estrogen of ovarian origin. In some species, estrone, synthesized in numerous tissues, is more abundant. In pregnancy, relatively more estriol is produced, and this comes from the placenta. The general pathway and the subcellular localization of the enzymes involved in the early steps of estradiol synthesis are the same as those involved in androgen biosynthesis. Features unique to the ovary are illustrated in Figure 42-7. 

Ohno, Y.I., Hirai, K.I., BCanoh, T., Uchino, H. andOgawa, K. (1982). Subcellular localization of H2O2 production in human neutrophils stimulated with particles and an eflfect of cytochalasin-B on the cells. Blood 60, 253-260. 

Kottke, Electron energy loss spectroscopy and imaging techniques for subcellular localization of elements in mycorrhizas. Methods Mierohiol. 23 369 (1991). 

Simpson, J. C., Wellenreuther, R., Poustka, A., Pepperkok, R., and Wiemann, S. (2000). Systematic subcellular localization of novel proteins identified by large-scale cDNA sequencing. EMBO Reports 1, 287-292. 

Chen, JY, Cheung, NH, Fung, MC, Wen, JM, Leung, WN, and Mak, NK, 2000. Subcellular localization of merocyanine 540 (MC540) and induction of apoptosis in murine myeloid leukemia cells. Photochem Photobiol 72, 114-120. 

Liu, A, N Pajkovic, Y Pang, D Zhu, B Calamini, AL Mesecar, and RB van Breemen. 2006. Absorption and subcellular localization of lycopene in human prostate cancer cells. Mol Cancer Ther 5(11) 2879-2885. 

Finally, the subcellular localization of CNTs is still controversial. Some reports showed that CNTs enter the cell without reaching the nucleus [140], whereas others demonstrated that CNTs can enter the nucleus [105, 141, 150]. Recently, Zhou et al. [151] demonstrated the possibility of manipulating the intracellular localization of noncovalently modified SWNTs by varying the conjugated molecule. 

Zhou, F.F. et al. (2010) New insights of transmembranal mechanism and subcellular localization of noncovalently... 

Juprelle-Soret, M., Wattiaux-Deconinck, S. and Wattiaux, R. (1988) Subcellular-localization of transglutaminase - effect of collagen. Biochemical Journal 250, 421-427. 

Brownlee, D.J.A., Fairweather, I., Thomdyke, M.C. and Johnston, C.F. (1996b) Cellular and subcellular localization of SALMFamide (Sl)-like immuno-reactivity within the central nervous system of the nematode Ascaris suum (Nematoda, Ascaroidea). Parasitology Research 82, 149-156. 

Fig. 9.1 Schematic diagram depicting drug transporters and their subcellular localization in the human small intestinal enterocyte (A), hepatocyte (B), and renal tubular cell (C).

Maliepaard M, Scheffer GL, Faneyte IF, van Gastelen MA, Pijnenborg AC, Schinkel AH et al. Subcellular localization and distribution of the breast cancer resistance protein transporter in normal human tissues. Cancer Res 2001 61(8)3458-3464. 

Consistent with their role as immune receptors, each human TLR is expressed by at least one subset of myeloid cells (MCs) or lymphocytes [7,8]. TLRs are also present on stromal elements like endothelium particularly after local inflammatory stimulus [9-11]. These distribution patterns can determine the physiological consequences of stimulation or antagonism, and affect the balance of toxicity versus therapeutic effect. Another consideration for medicinal chemistry is subcellular localization of TLRs. While most are expressed on the cell surface, some (TLRs 3,7,8, and 9) can localize to endosomes where they survey ingested material for ligands, so drug access to this compartment can be crucial when targeting these TLRs [12]. 

Haseloff, J., Siemering, K. R., Prasher, D. C. and Hodge, S. (1997). Removal of a cryptic intron and subcellular localization of green fluorescent protein are required to mark transgenic Arabidopsis plants brightly. Proc. Natl. Acad. Sci. USA 94, 2122-7. 

The calculation of protein proximity and hence association on the basis of sensitized emission or FSPIM requires correction for direct acceptor excitation and donor bleed through using several mathematical models and instrument correction factors [22, 59-61], which is difficult to control [22] (see also Chapters 7 and 8). A high detected acceptor to donor signal ratio in these techniques may also reflect other phenomena than FRET. For instance, this ratio is dependent on cellular expression levels and subcellular localizations, which are difficult to control. Additionally, for the widely used... 

Zelazny, E., Borst, J. W., Muylaert, M., Batoko, H., Hemminga, M. A. and Chaumont, F. (2007). FRET imaging in living maize cells reveals that plasma membrane aquaporins interact to regulate their subcellular localization. Proc. Natl. Acad. Sci. USA 104, 12359-64. 

Tinglu, G., Ghosh, A., and Ghosh, B.K. (1984) Subcellular localization of alkaline phosphatase in Bacillus licheniformis 749/C by immunoelectron microscopy with colloidal gold. J. Bacteriol. 159, 668. 

Tobin, D. et al. Combinatorial expression of TRPV channel proteins defines their sensory functions and subcellular localization in C. elegans neurons. Neuron 35 307-318,2002. 

Liischer, B. and Fritschy, J. M. (2001) Subcellular localization and regulation of GABAA receptors and associated proteins. Int. Rev. Neurobiol. 48, 31-64. 

Connolly, C. N., Uren, J. M Thomas, R, Gorrie, G. H., Gibson, A., Smart, T. G., and Moss, S. J. (1999) Subcellular localization and endocytosis of homomeric y2 subunit splice variants of y-aminobutyric acid type A receptors. Mol. Cell. Neurosci. 13,259-271. 

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