Subcellular targeting

Fig. 1.2 Protein blot analysis of human therapeutic protease inhibitor (HTPI) produced in alfalfa cell cultures using different promoters and subcellular targeting peptides as shown. Equal amounts of total soluble proteins from cell cultures were separated by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and blotted onto a polyvinyldifluoride (PVDF) membrane. Monoclonal anti-HTPI IgGs were used for detection.

Fig. 1.3 Prediction of the most appropriate subcellular targeting strategies by agroinfiltration. The levels of an industrial enzyme (IE) are shown in agroinfiltrated and transgenic alfalfa leaves using different subcellular targeting peptides. Equal amounts of total soluble leaf proteins were separated by SDS-PAGE and blotted onto a PVDF membrane. Polyclonal anti-IE IgGs were used for detection.

Fritschy, J. M., Johnson, D. K., Mohler, H., and Rudolph, U. (1998) Independent assembly and subcellular targeting of GABAa receptor subtypes demonstrated in mouse hippocampal and olfactory neurons in vivo. Neurosci. Lett. 249, 99-102. 

Subcellular targeting by membrane lipids. Curr Opin Cell Biol, 2001, 13(2), 146-52. 

Hurley, J. H. and S. Misra, Signaling and subcellular targeting by membrane-binding domains. Anna Rev Biophys Biomol Struct, 2000, 29,... 

Furthermore, sorting of epidermal growth factor (EGF) receptor to the lysosome was reduced and its recycling to the membrane increased. Flence this study exemplarily indicates the importance of each prenyl moiety as a determinant for the subcellular targeting. ... 

Grailhe R, de Carvalho LP, Pass Y, et al. Distinct subcellular targeting of fluorescent nicotinic alpha 3 beta 4 and serotoninergic 5-HT3A receptors in hippocampal neurons. Eur J Neurosci 2004 19(4) 855-862. 

Chromium(III) compounds are less genotoxic than chromium(VI) compounds in intact cell systems because of the relative inability of chromium(III) to cross cell membranes however, chromium(III) is more genotoxic than chromium(VI) when tested in vitro in subcellular targets (Kolwalski et al. 1996 Snow 1991 Snow and Xu 1989). The reduction of chromium(VI) to chromium(ni) as the ultimate genotoxicant within cells may account for the genotoxicity of chromium(VI) (Beyersmann and Koster 1987). 

All SABATH proteins characterized so far contain between 357 and 389 amino acids, and the molecular mass of the subunit ranges from 40-49 kDa. Size exclusion chromatography, performed with some of these enzymes, has revealed that the molecular mass of the native enzymes is roughly 80 kDa, indicating a dimeric structure. None of the SABATH proteins identified thus far have any obvious subcellular targeting signals. Cytosolic localization was experimentally confirmed for two of these enzymes, BAMT and CaMXMT.57,59... 

Another problem in protein expression is how to obtain a subcellular targetting. The plant cells (like all eukaryotic cells) consist of several compartments (e.g., nucleus, chloroplasts, mitochondria). The proteins that are expressed in compartments other than the cytosol usually have signal sequences that direct them to their subcellular destination. To direct a protein to the desired compartment, a fusion is effected between the signal sequence and the mature protein. Many such signal sequences have been identified and are available to direct proteins to practically any compartment. 

Ro, D.K. and Bohlmann, J. (2006) Diterpene resin acid biosynthesis in loblolly pine (Pinus taeda) functional characterization of abietadiene/levopimaradiene synthase (PtTPS-LAS) cDNA and subcellular targeting of PtTPS-LAS and abietadienol/abietadienal oxidase (PtAO, CYP720B1). Phytochemistry, 67, 1572-8. 

Subcellular targeting and differential S-nitrosylation of endothelial nitric-oxide synthase. J. Biol. Chem. 2006 281 151-157. 54. 

Haskins JR. Critical subcellular targets of cisplatin and related platinum analogs in rat renal proximal tubule cells. Kidney Internal. 1995 48 761-770. 40. 

Nordberg GF, Jin T, Nordberg M. Subcellular targets of cadmium nephrotoxicity cadmium binding to renal membrane proteins in animals with or without protective metallothionein synthesis. Environ Elealth Perspect 1994 102 (suppi 3) 191-194. 

Efficacy of therapeutically active drugs known to act on intracellular targets can be enhanced by specific delivery to the site of action. Triphenylphosphoniiun cations can be used to create subcellular targeted Hposomes that efficiently deliver drugs to mitochondria, thus enhancing their therapeutic action. 

A., Verger, R., Doherty, A., Merot, B. and Danzin, C. (2001) Large-scale production of a therapeutic protein in transgenic tobacco plants effect of subcellular targeting on quality of a recombinant dog gastric lipase. Molecular Breeding 7, 329-340. 

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