Proteins differentially expressed

Identification of proteins differentially expressed in HT-29 colon cancer cells after polyphenols treatment... 

Protein differentially expressed Wrong decision (Type II error P) Correct decision... 

Schoor, M., Schuster-Gossler, K., and Gossler, A. (1993). The etl-l gene encodes a nuclear protein differentially expressed during early mouse development. Dev. Dyn. 797 227-237. 

Hynes, S.O., McGuire, J., Fait, T., and Wadstrom, T. 2003, The rapid detection of low molecular mass proteins differentially expressed under biological stress for four Helicobacyter spp. using ProtemChip technology. Proteomics 3 217>-TI i. 

That is, the increase or decrease of protein expression in a given disease state can be entirely coincidental, the proteins in question being more like innocent bystanders than causative agents. The vast majority of the proteins differentially expressed in a given disease will fall into these two categories. ... 

Differentially expressed proteins Differentially expressed genes ... 

NFAT proteins are expressed in skeletal, cardiac, and smooth muscle and play important roles in the regulation of the development and differentiation of these tissues. In skeletal muscle, NFAT isoforms are expressed at different stages of development and regulate progression from early muscle cell precursors to mature myocytes. NFAT proteins have also been shown to control the expression of the myosin heavy chain and positively regulate muscle growth [1, 2]. 

PARs are coupled to multiple G-proteins and mediate a number of well-defined cellular responses via classical second messenger and kinase pathways. PARs are differentially expressed in cells of the vasculature as well in the brain, lung, gastrointestinal tract, skin as well as other highly vascularised tissues and evidence suggests distinct physiological functions and roles in disease states [2]. 

While the sequence of the human genome is known, the picture provided by genomics alone is both static and incomplete. Proteomics aims to identify the entire complement of proteins elaborated by a cell under diverse conditions. As genes are switched on and off, proteins are synthesized in particular cell types at specific times of growth or differentiation and in response to external stimuli. Muscle cells express proteins not expressed by neural cells, and the type of subunits present... 

SAUNDERS P T, SHARPE R M, WILLIAMS K, MACPHERSON S, URQUART H, IRVINE D S, MILLAR M R (2001) Differential expression of oestrogen receptor alpha and beta proteins in the testes and male reproductive system of human and non-human primates. Mol Hum Reprod. 7 227-36. 

Jia C. and Halpem M. (1996). Subclasses of vomeronasal receptor neurons differential expression of G-proteins (Gi-alpha2 Go-alpha) and segregated projections to the accessory olfactory-bulb. Brain Res 719, 117-128. 

Krishna N., Getchell M., Margolis F. and Getchell T. (1995). Differential expression of vomeromodulin and odorant-binding protein, putative pheromone and odorant transporters, in the developing rat nasal chemosensory mucosae. J Neurosci Res 40, 54-71. 

Wekesa K. and Anholt R. (1999). Differential expression of G-proteins in the mouse olfactory system. Brain Res 837, 117-126. 

Figure 3.1. Protein expression mapping using 2-D electrophoresis and mass spectrometry. The purpose is to compare protein expression patterns between cell types or in the same cell type under different growth conditions. Proteins are extracted from the different cell types and separated by 2D gel electrophoresis. Image analysis programs are used to compare the spot intensities between gels and identify proteins that are differentially expressed. The protein of interest is excised from the gel and its identity is determined by mass spectrometry. The power of the method increases greatly if the identity of a large number of proteins on the gel is known and present in a database because information can then be obtained without further mass spectrometry.

For these reasons we have developed a different approach that measures differential expression of intact proteins.21 In this approach the proteins are extracted from the cell, separated on an HPLC column, ionized via electrospray, and automatically deconvoluted into their respective uncharged nominal masses. By this methodology it is then possible to obtain accurate, intact protein profiles of the individual strains of bacteria. Because the masses of the detected proteins are accurate to +2 Da from run to run, it is possible to subtract protein profiles from known strains to quickly identify differences in protein expression among newly mutated strains. 

The feasibility of this approach to not only differentiate pathogenic and nonpathogenic strains of bacteria based on significant differences in protein mass but also on the basis of variations in levels of protein expression was demonstrated using a method for quantitating protein expression by LC/MS of whole proteins.54 This method is based on the fact that some proteins present in cells are abundant universal proteins whose expression levels exhibit little variation. This method demonstrates that these co-extracted proteins can be used as internal standards to which the other proteins in the sample can be compared. By comparing the intensities of a selected protein to a marker protein, or internal standard, a relative ratio is obtained. This ratio... 

As described above all samples were separated online using LCT ESI-TOF-MS then normalized for relative quantitation using a bovine insulin internal standard. Fractions were then collected for MAFDI-TOF-MS PMF, digested with modified porcine trypsin, and analyzed using the TofSpec2E. Following this analysis, three major classes of differentially expressed including proteins were revealed in these... 

TABLE 10.1 Differentially Expressed Proteins in MCF10 Cell Lines... 

Jasmer, D.P., Bohnet, S. and Prieur, D.J. (1991) Trichinella spp. differential expression of acid phosphatase and myofibrillar proteins in infected muscle cells. Experimental Parasitology 72, 321-331. 

Witzmann FA et al. Differential expression of cytosolic proteins in the rat kidney cortex and medulla preliminary proteomics. Electrophoresis 1998 19 2491-2497. 

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