Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.25.1 (proteasome)
28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cationic proteins of brain lysosomes (LCP), myelin (MCP) and nuclear histone fractions from calf thymus (T) and rat brain (B) are shown to increase at different degree the permeability of brain lysosomes and neutrophiles for acid RNAase, acid phosphatase, catepsin D and beta-galactosidase. According to the effectivity, basic proteins can be listed in the following order: for lysosomes-f2aT, F3B, f3T greater than total histones B, f2bT greater than f2B greater than LCP, MCP greater than flT, flB; for neutriphiles-f3T larger than or equal to total histones B larger than or equal to f3b MCP larger than or equal to f2aT, f2bT greater than f2B greater than LCP greater than flB greater than flT. Fractions f2a and f3 considerably increased the release of acid RNAase from lysosomes in very low concentrations beginning from 0,2 mug/ml, while the release of catepsine and acid phosphatase took place beginning from 5-10 mug/ml. The effect of lysosome and myelin cationic proteins on the release of hydrolases occurred at concentrations ten to hundred times higher.
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PMID:[Effect of brain and thymus cationic proteins on membrane permeability]. 120 52

During a three-day fast, followed by four days of refeeding, the content of the multicatalytic proteinase as well as hydrolyzing activity towards Suc-Leu-Leu-Val-Tyr-7-amino-4-methylocoumarin (SLLVT-MCA) was measured in various rat tissues. When compared with normal rats, the MCP content, as determined by immunochemical techniques, was unchanged over the entire experimental period in the three tissues examined: gastrocnemius muscle, thymus and testis. By contrast, a differential response was observed in the three tissues with respect to specific and total SLLVT-MCA splitting activity: for thymus and testis, these values were again unchanged, whereas in gastrocnemius muscle, both specific and total enzyme activity fell by almost 70% on day three of fasting but returned to control values on day four of refeeding. This change in activity was not due to the accumulation or degradation of a specific proteinase inhibitor. Data demonstrate that, in association with the insulin-deficient state of starvation, the activity of the multicatalytic proteinase shows an adaptive behaviour which becomes manifest in some but not in other tissues.
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PMID:Tissue-specific changes of multicatalytic proteinase activity in the fasted rat. 184 9

The proteasome (high-molecular-mass multicatalytic proteinase complex) is composed of a large number of non-identical protein subunits of the alpha and beta types. The mouse beta-type subunits LMP2 and LMP7 (LMP, low-molecular-mass protein) are encoded within the mouse major histocompatibility complex (MHC II) region, and are thought to connect the proteasome to the MHC class-I antigen-processing pathway. In the present communication, we have analysed the two proteasome subunits with regard to their identity within the proteasome complex, their protein levels, their amounts of mRNA in different mouse tissues and cell lines, and have investigated the intracellular localization of LMP2 and LMP7 subunits in thymus and liver by immunocytology. Our experiments indicate that LMP2 and LMP7 subunits are synthesized as precursor proteins of 24 kDa and 30 kDa, respectively, and that only the processed 21-kDa and 23-kDa subunits are part of the 20S proteasome complex. The proportion of LMP2-subunit-containing and LMP7-subunit-containing proteasome complexes, as well as LMP2 and LMP7 mRNA levels, vary strongly and are shown to be dependent on the tissues or cell lines analysed. Furthermore, high LMP2 and LMP7 mRNA levels do not always correlate with high protein levels, suggesting a specific translational mechanism which controls proteasome subunit synthesis. Generally, mRNA levels appear to be particularly high in those tissues which are known to be involved in MHC class-I antigen presentation. Immunocytological analysis shows a strong nuclear localization of the subunits in cells of the thymus, while in the liver they appear to be evenly distributed between the two cellular compartments. Our data support the idea that both LMP2 and LMP7 proteins are non-essential proteasome subunits which are probably involved in the regulation of proteasome activities. The function of the two subunits, however, may not be restricted to the proposed role of proteasomes in antigen presentation.
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PMID:The major-histocompatibility-complex-encoded beta-type proteasome subunits LMP2 and LMP7. Evidence that LMP2 and LMP7 are synthesized as proproteins and that cellular levels of both mRNA and LMP-containing 20S proteasomes are differentially regulated. 836 98

LMP7 is one of the two proteasome subunits encoded in the major histocompatibility complex and is speculated to play a role in the generation of endogenous peptides for presentation by class I molecules to cytotoxic T cells. Here we report the genomic organization of the mouse Lmp-7 gene and the tissue distribution of its messenger RNA. In contrast to human LMP7 which is composed of seven exons and six introns, the mouse Lmp-7 gene is organized in six exons and five introns. Interestingly, the region corresponding to the first exon of human LMP7 is highly modified by numerous insertions and deletions and contains two in frame stop codons. Consequently, the mouse Lmp-7 gene does not allow the alternative exon usage described in humans and most likely encodes for only one LMP7 protein. Thus, the Tap-1 3' end gene region and the Lmp-7 initial translation codon are separated by an 1182 nucleotide region which contains a TATA-box, a cAMP regulatory element, two SP1 sites, and two G-C-rich regions. Expression of the Lmp-7 messenger RNA was analyzed on different tissues from unstimulated mice. Lmp-7 messenger RNA is expressed in spleen, thymus, lung, liver, heart, and, at a very low level, in kidney but not in brain and testis. The possible role of Lmp genes in antigen processing is discussed.
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PMID:Genomic organization and tissue expression of the mouse proteasome gene Lmp-7. 840 12

The primary structures of the interferon-gamma-inducible mouse 20S proteasome subunit MECL-1 and its alternate homolog MC14 were determined. Northern analysis of mouse tissues revealed that MECL-1 mRNA predominantly occurred in thymus, lymph nodes, and spleen, whereas small amounts were detected in non-lymphoid tissues such as kidney, muscle, and testis. Unexpectedly, probing RNA blots with MC14 showed that tissues with high MECL-1 expression contained little MC14 and vice versa. A very similar reciprocal tissue expression was subsequently found for the homologous subunit pairs LMP2 and delta as well as LMP7 and MB1. The subunit protein composition of 20S proteasomes purified from liver, thymus, and lung reflected RNA expression. The impact of a regulated reciprocal tissue expression is discussed with respect to thymic selection and the induction of tolerance in potentially autoreactive T cells.
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PMID:Molecular cloning of the mouse proteasome subunits MC14 and MECL-1: reciprocally regulated tissue expression of interferon-gamma-modulated proteasome subunits. 917 9

We have cloned the mouse PA28 proteasome activator cDNAs. Northern blot demonstrates high PA28 mRNA levels in liver, kidney and lung. mRNA levels are low in thymus, spleen and brain. In contrast, PA28 protein levels vary little between these tissues. Immunocytological analysis and cell fractionation experiments demonstrate that both subunits are almost equally distributed between the cytoplasm and the nucleus. Interestingly, PA28alpha spares nucleoli, while PA28beta is strongly enhanced in the nucleolus. This indicates for the first time that the PA28alpha and PA28beta subunits may serve nuclear functions which may be different from and independent of each other.
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PMID:Expression and subcellular localization of mouse 20S proteasome activator complex PA28. 928 11

Proteasomes are nonlysosomal multicatalytic proteases involved in antigen processing. Three of the 10 mammalian proteasome beta subunits (LMP2, LMP7, and LMP10) are induced by IFN-gamma. Two of these (LMP2 and LMP7) are encoded in the major histocompatibility complex of both human (chromosome 6) and mouse (chromosome 17). However, the human homologue of Lmp10, MECL1, is found on chromosome 16. Here we show that in mice, Lmp10 is a single-copy gene localized to chromosome 8, in a region of conserved synteny with human chromosome 16. Sequencing of a 129/SvJ strain genomic clone revealed that the gene has eight exons spanning 2.3 kb. Characterization of a full-length mouse cDNA clone indicates that Lmp10 encodes a protein of 273 amino acids with a calculated molecular weight of 29 kDa and an isoelectric point of 6.86. Northern analysis of Lmp2, Lmp7, and Lmp10 showed expression in heart, liver, thymus, lung, and spleen, but not in brain, kidney, skeletal muscle, or testis.
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PMID:DNA sequence, chromosomal localization, and tissue expression of the mouse proteasome subunit lmp10 (Psmb10) gene. 936 87

The multicatalytic proteinase complex (MPC or proteasome) from bovine thymus was isolated and purified to homogeneity applying a protocol utilizing ion exchange and gel permeation chromatography as major purification tools. The purified complex shows molecular properties that are common for proteasomal molecules (high molecular mass, multisubunit organization, and multiple proteolytic activities) even though a peculiar subunit composition and the presence of specific regulatory mechanisms affecting the assembled proteolytic activities suggest a specialized function for this complex. Thymus proteasome is characterized by the presence of LMP2, LMP7, and LMP10 (MECL1) subunits, which replace the X, Y, and Z subunits. Since a similar complex was previously isolated in bovine spleen, it appears that the proteasomal population containing the LMP subunits is characteristic for organs involved in immune response. Both the thymus and spleen proteasomes are characterized by a marked efficiency in cleaving peptide bonds after branched-chain and aromatic amino acids, indicating that this proteasomal population is most likely involved in intracellular processing of class I antigenic peptides and is an example of an "in vivo" functioning immunoproteasome. However, in spite of several similarities, the complexes isolated from the two lymphoid organs do not show superimposable functional properties, which suggests the presence of organ-specific regulatory mechanisms affecting each of the proteolytic components assembled in the complex.
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PMID:Isolation and characterization of bovine thymus multicatalytic proteinase complex. 1068 46

We report the identification and radiation hybrid mapping of members of the proteasome/ubiquitin system in pigs that, so far, have only been identified in humans and cattle. Expressed sequence tags (ESTs) were constructed from ten oligo(dT)-primed individually tagged, directionally cloned and normalized cDNA libraries from peripheral blood cells (PBC), spleen (Sp), thymus (Th), lymph node (LN) and bone marrow (BM) from immunologically naive and challenged pigs as part of an implant-associated orthopedic infection model. The ESTs mapped using the 7000 rad IMpRH panel (Hawken et al., 1999) were ubiquitin fusion-degradation 1 like protein (UFD1L), ubiquitin activating enzyme E1 and ubiquitin-S27a fusion protein which mapped to porcine chromosomes 14, 7 and X, respectively.
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PMID:Identification and radiation hybrid mapping of members of the porcine proteasome/ubiquitin system. 1072 27

The proteasome is an eukaryotic multi-subunit protease complex composed of one 20S core component and two 19S regulatory complexes. The regulatory complex contains 6 putative ATPases. We investigated tissue and cell distribution of one of these ATPases, MSS1 (mammalian suppressor of sgv1). MSS1 was ubiquitously present in rat tissues as was the 20S core component of proteasome. However, the ratio of MSS1 to 20S varied greatly among tissues and MSS1 was concentrated in the thymus. Glycerol gradient sedimentation analysis revealed that MSS1 is included in protein complexes whose density is lighter than that of the proteasome. MSS1 was distributed in mammalian cells ubiquitously, while proteasome was rather concentrated in the nuclei. Hence, a novel molecular status of MSS1 distinct from proteasome is implicated. Interestingly, multiple basal transcription factors for RNA polymerase II, including TBP, TFIIB, TFIIH, and TFIIF, were found to be associated with MSS1. These results suggest that MSS1, in addition to proteolysis, plays a role in DNA metabolism including transcriptional regulation.
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PMID:Tissue and cell distribution of a mammalian proteasomal ATPase, MSS1, and its complex formation with the basal transcription factors. 1111 27


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