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Cellular Locations (cellular + locations)
Selected AbstractsDiscovery, regulation, and action of the major apoptotic nucleases DFF40/CAD and endonuclease GJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2005Piotr Widlak Abstract Toward the end of the 20th and beginning of the 21st centuries, clever in vitro biochemical complementation experiments and genetic screens from the laboratories of Xiaodong Wang, Shigekazu Nagata, and Ding Xue led to the discovery of two major apoptotic nucleases, termed DNA fragmentation factor (DFF) or caspase-activated DNase (CAD) and endonuclease G (Endo G). Both endonucleases attack chromatin to yield 3,-hydroxyl groups and 5,-phosphate residues, first at the level of 50,300 kb cleavage products and next at the level of internucleosomal DNA fragmentation, but these nucleases possess completely different cellular locations in normal cells and are regulated in vastly different ways. In non-apoptotic cells, DFF exists in the nucleus as a heterodimer, composed of a 45 kD chaperone and inhibitor subunit (DFF45) [also called inhibitor of CAD (ICAD-L)] and a 40 kD latent nuclease subunit (DFF40/CAD). Apoptotic activation of caspase-3 or -7 results in the cleavage of DFF45/ICAD and release of active DFF40/CAD nuclease. DFF40's nuclease activity is further activated by specific chromosomal proteins, such as histone H1, HMGB1/2, and topoisomerase II. DFF is regulated by multiple pre- and post-activation fail-safe steps, which include the requirements for DFF45/ICAD, Hsp70, and Hsp40 proteins to mediate appropriate folding during translation to generate a potentially activatable nuclease, and the synthesis in stoichiometric excess of the inhibitors (DFF45/35; ICAD-S/L). By contrast, Endo G resides in the mitochondrial intermembrane space in normal cells, and is released into the nucleus upon apoptotic disruption of mitochondrial membrane permeability in association with co-activators such as apoptosis-inducing factor (AIF). Understanding further regulatory check-points involved in safeguarding non-apoptotic cells against accidental activation of these nucleases remain as future challenges, as well as designing ways to selectively activate these nucleases in tumor cells. © 2005 Wiley-Liss, Inc. [source] Restoration of antibacterial activity of ,-lactams by epigallocatechin gallate against ,-lactamase-producing species depending on location of ,-lactamaseJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2003Wei-Hua Zhao The combined effects of (,)-epigallocatechin gallate (EGCg) and ,-lactams were investigated against various ,-lactamase-producing clinical isolates, including 21 Staphylococcus aureus, 6 Escherichia coli, 3 Klebsiella pneumoniae and 8 Serratia marcescens strains. Penicillin in combination with EGCg at 12.5,g mL,1 showed the most potent synergy against 100% penicillinase-producing S. aureus. However, cefotaxime or imipenem in combination with higher concentration of EGCg (100 ,g mL,1) only showed slight synergy against 2 of 17 Gram-negative rods. Similar to the effect on the penicillinase from S. aureus, however, EGCg also directly inhibited the extracted ,-lactamases from the Gram-negative rods, thereby protecting ,-lactams from inactivation. The different effects of the combinations on different ,-lactamase-producing species were confirmed to be related to the cellular locations of ,-lactamases. In contrast to a 32.7% extracellular fraction of total ,-lactamase activity in a penicillinase-producing S. aureus, the fractions were 0.6%, 0.6% and 1.2% in a TEM-derived extended-spectrum ,-lactamase-producing E. coli, an inhibitor-resistant ,-lactamase-producing K. pneumoniae and an IMP-producing S. marcescens, respectively. In conclusion, the combination of penicillin with EGCg showed potent synergy against penicillinase-producing S. aureus in-vitro. The combinations of ,-lactams and EGCg against ,-lactamase-producing Gram-negative rods do indicate a limitation owing to the cellular location of ,-lactamases. [source] Expression of a novel T-complex testis expressed 5 (Tctex5) in mouse testis, epididymis, and spermatozoaMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 9 2007Y.B. Han Abstract Expression of T-complex testis expressed 5 (Tctex5), an orthologue of protein phosphatase-1 inhibitor-3 (PPP1R11), was enhanced in mouse testis and was also expressed in epididymis and spermatozoa. There were three transcripts of Tctex5 including one brain specific and two common transcripts dominant in mouse testis. Tctex5 protein isoforms (75, 52, 32, 25, and 14.3 kDa) were identified. Isoforms of 75 and 52 kDa were spermatogenic-specific and were found in protein fraction containing nuclei, mitochondria, and flagellum accessory, and also in protein fraction containing mainly membranes. Tctex5 was localized in nuclei of pachytene spermatocytes, round spermatocytes, cytoplasm of Sertoli cells in testis; cilia, secretion bodies and nuclei of epithelial cells and interstitium smooth muscle cells in epididymis; and head and principal piece of tail in epididymal spermatozoa. The results suggested that Tctex5 might be a specific protein phosphatase-1 inhibitor in sperm; various Tctex5 transcripts and isoforms and cellular locations imply its different roles in spermatogenesis. Nuclei-type isoforms (75 and 52 kDa) might take part in nucleus remodeling during spermatogenesis whilst membrane-type isoform (52 kDa) might be responsible for dephosphorylation of proteins during capacitation. The other isoforms might play general roles for all kinds of cell types. Mol. Reprod. Dev. 74: 1132,1140, 2007. © 2007 Wiley-Liss, Inc. [source] Detailed proteome analysis of growing cells of the planctomycete Rhodopirellula baltica SH1TPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2008Cao Xuan Hieu Abstract Rhodopirellula baltica SH1T, which was isolated from the water column of the Kieler Bight, a bay in the southwestern Baltic Sea, is a marine aerobic, heterotrophic representative of the ubiquitous bacterial phylum Planctomycetes. We analyzed the R. baltica proteome by applying different preanalytical protein as well as peptide separation techniques (1-D and 2-DE, HPLC separation) prior to MS. That way, we could identify a total of 1115 nonredundant proteins from the intracellular proteome and from different cell wall protein fractions. With the contribution of 709 novel proteins resulting from this study, the current comprehensive R. baltica proteomic dataset consists of 1267 unique proteins (accounting for 17.3% of the total putative protein-coding ORFs), including 261 proteins with a predicted signal peptide. The identified proteins were functionally categorized using Clusters of Orthologous Groups (COGs), and their potential cellular locations were predicted by bioinformatic tools. A unique protein family that contains several YTV domains and is rich in cysteine and proline was found to be a component of the R. baltica proteinaceous cell wall. Based on this comprehensive proteome analysis a global schema of the major metabolic pathways of growing R. baltica cells was deduced. [source] Tissue Distribution of P-Glycoprotein in CatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009S. Van Der Heyden Summary Permeability glycoprotein (P-gp) is a membrane-bound efflux pump that exports various substances out of the cell. Variations in P-gp expression play an important role in susceptibility to toxic substances, drug efficacy and disease risk. In the present study, the distribution of the MDR1 -gene product P-gp was determined in normal tissues of domestic shorthair cats using immunohistochemistry. Two monoclonal antibodies C494 and C219 were used, recognizing a different epitope on the human P-gp molecule. A consistent positive immunolabelling was obtained. The tissue distribution and cellular locations with antibody C494 were similar to those in man and dogs; with liver, colon, adrenal cortex and brain capillaries being consistently and intensely labelled. However, the immunolabelling in the kidney was in contradiction to man and dogs. The C219 antibody seems to react with a specific form of P-gp, only expressed in feline tissues with a barrier function, i.e. endothelia of the brain, testes and ovaries, and intestinal epithelial cells in contact with the lumen. [source] Localization of voltage-sensitive L-type calcium channels in the chicken retinaCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2001Sally I Firth PhD ABSTRACT L-type calcium channels have been associated with synaptic transmission in the retina, and are a potential site for modulation of the release of neurotransmitters. The present study documents the immunohistochemical localization of neuronal ,1 subunits of L-type calcium channels in chicken retina, using antibodies to the ,1c, ,1d and ,1f subunits of L-type calcium channels. The ,1c-like subunits were localized to Müller cells, with predominantly radial processes, and a prominent band of horizontal processes in the outer plexiform layer. The antibody to ,1d subunits labelled most, if not all, cell bodies. The antibody to a human ,1f subunit strongly labelled photoreceptor terminals. Fainter immunoreactivity was detected in the inner segments of the photoreceptors, a subset of amacrine cells, two bands of labelling in the inner plexiform layer and many ganglion cells. The differential cellular distributions of these ,1-subunits suggests subtle functional differences in their roles at different cellular locations. [source] | |||||||||||||