Direct binding of glyceraldehyde 3-phosphate dehydrogenase to telomeric DNA protects telomeres against chemotherapy-induced rapid degradation
| Autor: | Eleanor K. Spicer, John E. Baatz, Christopher Davies, Neil A. Demarse, Suriyan Ponnusamy, Elif Apohan, Besim Ogretmen |
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| Rok vydání: | 2009 |
| Předmět: |
Mutation
Missense DNA Single-Stranded Antineoplastic Agents Electrophoretic Mobility Shift Assay medicine.disease_cause Deoxycytidine Article law.invention chemistry.chemical_compound stomatognathic system Structural Biology law Cell Line Tumor medicine Humans Electrophoretic mobility shift assay Binding site Molecular Biology Glyceraldehyde 3-phosphate dehydrogenase Mutation Binding Sites biology Oligonucleotide Telomere Molecular biology Gemcitabine Kinetics chemistry Amino Acid Substitution Doxorubicin biology.protein Recombinant DNA Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+) DNA Protein Binding |
| Zdroj: | Journal of molecular biology. 394(4) |
| ISSN: | 1089-8638 |
| Popis: | GAPDH (glyceraldehyde 3-phosphate dehydrogenase) is a glycolytic enzyme that displays several non-glycolytic activities, including the maintenance and/or protection of telomeres. In this study, we determined the molecular mechanism and biological role of the interaction between GAPDH and human telomeric DNA. Using gel shift assays, we show that recombinant GAPDH binds directly with high affinity (Kd = 45 nM) to a single-stranded oligonucleotide comprising three telomeric DNA repeats and that nucleotides T1, G5 and G6 of the TTAGGG repeat are essential for binding. The stoichiometry of the interaction is 2:1 (DNA: GAPDH), and GAPDH appears to form a high-molecular weight complex when bound to the oligonucleotide. Mutation of Asp32 and Cys149, which are localized to the NAD-binding site and the active site center of GAPDH, respectively, produced mutants that almost completely lost their telomere-binding functions both in vitro and in situ (in A549 human lung cancer cells). Treatment of A549 cells with the chemotherapeutic agents gemcitabine and doxorubicin resulted in increased nuclear localization of expressed wild-type GAPDH, where it protected telomeres against rapid degradation, concomitant with increased resistance to the growth inhibitory effects of these drugs. The non-DNA-binding mutants of GAPDH also localized to the nucleus when expressed in A549 cells, but did not confer any significant protection of telomeres against chemotherapy-induced degradation or growth inhibition, and this occurred without the involvement of caspase activation or apoptosis regulation. Overall, these data demonstrate that GAPDH binds telomeric DNA directly in vitro and may have a biological role in the protection of telomeres against rapid degradation in response to chemotherapeutic agents in A549 human lung cancer cells. |
| Databáze: | OpenAIRE |
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