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Literature summary for 2.7.7.8 extracted from
- Human polynucleotide phosphorylase (hPNPase(old-35)): an evolutionary conserved gene with an expanding repertoire of RNA degradation functions (2011), Oncogene, 30, 1733-1743.
Application
| Application | Comment | Organism |
|---|---|---|
| molecular biology | targeted overexpression of hPNPase represents a strategy to selectively downregulate RNA expression and consequently intervene in a variety of pathophysiological conditions | Homo sapiens |
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| gene cloning using an overlapping pathway screening strategy designed to identify genes coordinately regulated during the processes of cellular differentiation and senescence, overview. Expression in HO-1 cells | Homo sapiens |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| additional information | targeted overexpression of hPNPase represents a strategy to selectively downregulate RNA expression and consequently intervene in a variety of pathophysiological conditions, enzyme silencing in PNPase RNA interference-transfected HEK293 cells | Homo sapiens |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| cytoplasm | - |
Homo sapiens | 5737 | - |
| mitochondrion | mammalian PNPase contains an N-terminal mitochondrial localization signal facilitating its subcellular localization in mitochondria | Mus musculus | 5739 | - |
| mitochondrion | mammalian PNPase contains an N-terminal mitochondrial localization signal facilitating its subcellular localization in mitochondria | Homo sapiens | 5739 | - |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| additional information | Homo sapiens | PNPase, as a phosphorylase, incorporates phosphate and ADP in degradation and polymerization process, respectively. The specificity of the enzyme for the polymerization reaction is high for ADP, with much less activity for other nucleotide diphosphates and no activity for ATP or other nucleotide triphosphates. The human PNPase displays no preferential activity for polyadenylated RNA like bacterial or chloroplast PNPase | ? | - |
? |  |
| RNAn+1 + phosphate | Mus musculus | - |
RNAn + a nucleoside diphosphate | - |
r | |
| RNAn+1 + phosphate | Homo sapiens | - |
RNAn + a nucleoside diphosphate | - |
r | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Homo sapiens | - |
- |
- |
| Mus musculus | - |
- |
- |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| C-8161 cell | - |
Homo sapiens | - |
| FM-516-SV cell | - |
Homo sapiens | - |
| HEK-293 cell | - |
Homo sapiens | - |
| HO-1 cell | - |
Homo sapiens | - |
| liver | - |
Mus musculus | - |
| melanocyte | - |
Homo sapiens | - |
| MeWo cell | - |
Homo sapiens | - |
| additional information | enzyme expression level analysis, overview | Homo sapiens | - |
| NHEM-neo cell | - |
Homo sapiens | - |
| WM-278 cell | - |
Homo sapiens | - |
| WM-35 cell | - |
Homo sapiens | - |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| microRNAn+1 + phosphate | recombinantly expressed microRNAs miR-let7a, miR-106b, miR-25, miR-221, miR-222, and miR-184 | Homo sapiens | microRNAn + ADP | - |
r | |
| additional information | PNPase, as a phosphorylase, incorporates phosphate and ADP in degradation and polymerization process, respectively. The specificity of the enzyme for the polymerization reaction is high for ADP, with much less activity for other nucleotide diphosphates and no activity for ATP or other nucleotide triphosphates. The human PNPase displays no preferential activity for polyadenylated RNA like bacterial or chloroplast PNPase | Homo sapiens | ? | - |
? | |
| additional information | in the cytoplasm, human enzyme, from adenoviral-mediated overexpression, can directly degrade c-myc mRNA by virtue of its 3'-5' exoribonuclease property, and this degradation is specific for c-myc as compared with other mRNAs, such as c-jun, glyceraldehyde 3-phosphate dehydrogenase or GADD 34. In melanoma cells, degradation of microR-221 by hPNPase is more profound compared with other miRNAs | Homo sapiens | ? | - |
? | |
| RNAn+1 + phosphate | - |
Mus musculus | RNAn + a nucleoside diphosphate | - |
r | |
| RNAn+1 + phosphate | - |
Homo sapiens | RNAn + a nucleoside diphosphate | - |
r | |
Subunits
| Subunits | Comment | Organism |
|---|---|---|
| More | two conserved catalytic RNase PH regions, are present at the N-terminus of the enzyme | Homo sapiens |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| hPNPaseold-35 | - |
Mus musculus |
| hPNPaseold-35 | - |
Homo sapiens |
| PNPase | - |
Mus musculus |
| PNPase | - |
Homo sapiens |
| polynucleotide phosphorylase | - |
Mus musculus |
| polynucleotide phosphorylase | - |
Homo sapiens |
General Information
| General Information | Comment | Organism |
|---|---|---|
| evolution | human polynucleotide phosphorylase is an evolutionary conserved RNA-processing enzyme. PNPase contains five motifs that are conspicuously preserved through evolution extending from prokaryotes and plants to mammals. Although hPNPase structurally and biochemically resembles PNPase of other species, overexpression and inhibition studies reveal that hPNPase has evolved to serve more specialized and diversified functions in humans | Homo sapiens |
| malfunction | in a liver mitochondria from a liver-specific PNPase knockout mouse model, the decrease in functional electron transport chain complexes is responsible for decreased respiration. Liver mitochondria from liver-specific knockout mice display disordered circular and smooth inner membrane criste, similar to mitochondria having impaired components of oxidative phosphorylation pathways. Citrate synthase activity, routinely used as a marker of aerobic capacity, also decreases in the liver of PNPase knockout mice compared with the wild-type mice | Mus musculus |
| metabolism | the enzyme is involved in RNA degradation and/turnover, major processes controlling RNA levels and important regulators of physiological and pathological processes | Homo sapiens |
| additional information | two conserved catalytic RNase PH regions, a small domain of about 250 amino acid residues involved primarily in the 3' processing of transfer RNA precursors, are present at the N-terminus of the human enzyme. The RNA-binding property of hPNPase is conferred by two C-terminal RNA-binding domains, KH and S1 | Homo sapiens |
| physiological function | pivotal role of PNPase in mitochondrial morphogenesis and respiration in vivo | Mus musculus |
| physiological function | polynucleotide phosphorylase is an RNA-processing enzyme with expanding roles in regulating cellular physiology. By executing exonuclease activity PNPase specifically degrades mature miRNAs, schematic model of microRNA biogenesis and stability, overview. The enzyme might have an essential role in senescence- and differentiation-associated growth inhibition, involvement of hPNPase in producing pathological changes associated with aging by generating pro-inflammatory cytokines via reactive oxygen species and NF-kappaB, growth inhibition in different cancer cells and its molecular mechanism, overview. Direct involvement of PNPase in regulating specific cytosolic RNA import into the mitochondrial matrix, independently of its RNA-processing function | Homo sapiens |
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