Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport
Transketolase (TKT) is an essential thiamine diphosphate (ThDP)-dependent enzyme of the non-oxidative branch of the pentose phosphate pathway, with the glucose-6P flux through the pathway regulated in various medically important conditions. Here, we characterize the brain TKT regulation by acylation...
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MDPI AG
2024-01-01
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| Series: | International Journal of Molecular Sciences |
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| author | Vasily A. Aleshin Thilo Kaehne Maria V. Maslova Anastasia V. Graf Victoria I. Bunik |
| author_facet | Vasily A. Aleshin Thilo Kaehne Maria V. Maslova Anastasia V. Graf Victoria I. Bunik |
| author_sort | Vasily A. Aleshin |
| collection | DOAJ |
| description | Transketolase (TKT) is an essential thiamine diphosphate (ThDP)-dependent enzyme of the non-oxidative branch of the pentose phosphate pathway, with the glucose-6P flux through the pathway regulated in various medically important conditions. Here, we characterize the brain TKT regulation by acylation in rats with perturbed thiamine-dependent metabolism, known to occur in neurodegenerative diseases. The perturbations are modeled by the administration of oxythiamine inhibiting ThDP-dependent enzymes in vivo or by reduced thiamine availability in the presence of metformin and amprolium, inhibiting intracellular thiamine transporters. Compared to control rats, chronic administration of oxythiamine does not significantly change the modification level of the two detected TKT acetylation sites (K6 and K102) but doubles malonylation of TKT K499, concomitantly decreasing 1.7-fold the level of demalonylase sirtuin 5. The inhibitors of thiamine transporters do not change average levels of TKT acylation or sirtuin 5. TKT structures indicate that the acylated residues are distant from the active sites. The acylations-perturbed electrostatic interactions may be involved in conformational shifts and/or the formation of TKT complexes with other proteins or nucleic acids. Acetylation of K102 may affect the active site entrance/exit and subunit interactions. Correlation analysis reveals that the action of oxythiamine is characterized by significant negative correlations of K499 malonylation or K6 acetylation with TKT activity, not observed upon the action of the inhibitors of thiamine transport. However, the transport inhibitors induce significant negative correlations between the TKT activity and K102 acetylation or TKT expression, absent in the oxythiamine group. Thus, perturbations in the ThDP-dependent catalysis or thiamine transport manifest in the insult-specific patterns of the brain TKT malonylation and acetylations. |
| first_indexed | 2024-03-08T09:53:49Z |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-08T09:53:49Z |
| publishDate | 2024-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-6a6d1de071494f4ca7290999534c38c52024-01-29T13:55:34ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672024-01-0125291710.3390/ijms25020917Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine TransportVasily A. Aleshin0Thilo Kaehne1Maria V. Maslova2Anastasia V. Graf3Victoria I. Bunik4Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, RussiaInstitute of Experimental Internal Medicine, Otto von Guericke University, 39106 Magdeburg, GermanyFaculty of Biology, Lomonosov Moscow State University, 119234 Moscow, RussiaBelozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, RussiaBelozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, RussiaTransketolase (TKT) is an essential thiamine diphosphate (ThDP)-dependent enzyme of the non-oxidative branch of the pentose phosphate pathway, with the glucose-6P flux through the pathway regulated in various medically important conditions. Here, we characterize the brain TKT regulation by acylation in rats with perturbed thiamine-dependent metabolism, known to occur in neurodegenerative diseases. The perturbations are modeled by the administration of oxythiamine inhibiting ThDP-dependent enzymes in vivo or by reduced thiamine availability in the presence of metformin and amprolium, inhibiting intracellular thiamine transporters. Compared to control rats, chronic administration of oxythiamine does not significantly change the modification level of the two detected TKT acetylation sites (K6 and K102) but doubles malonylation of TKT K499, concomitantly decreasing 1.7-fold the level of demalonylase sirtuin 5. The inhibitors of thiamine transporters do not change average levels of TKT acylation or sirtuin 5. TKT structures indicate that the acylated residues are distant from the active sites. The acylations-perturbed electrostatic interactions may be involved in conformational shifts and/or the formation of TKT complexes with other proteins or nucleic acids. Acetylation of K102 may affect the active site entrance/exit and subunit interactions. Correlation analysis reveals that the action of oxythiamine is characterized by significant negative correlations of K499 malonylation or K6 acetylation with TKT activity, not observed upon the action of the inhibitors of thiamine transport. However, the transport inhibitors induce significant negative correlations between the TKT activity and K102 acetylation or TKT expression, absent in the oxythiamine group. Thus, perturbations in the ThDP-dependent catalysis or thiamine transport manifest in the insult-specific patterns of the brain TKT malonylation and acetylations.https://www.mdpi.com/1422-0067/25/2/917transketolasemalonylationacetylationsirtuin 5oxythiaminemetformin |
| spellingShingle | Vasily A. Aleshin Thilo Kaehne Maria V. Maslova Anastasia V. Graf Victoria I. Bunik Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport International Journal of Molecular Sciences transketolase malonylation acetylation sirtuin 5 oxythiamine metformin |
| title | Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport |
| title_full | Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport |
| title_fullStr | Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport |
| title_full_unstemmed | Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport |
| title_short | Posttranslational Acylations of the Rat Brain Transketolase Discriminate the Enzyme Responses to Inhibitors of ThDP-Dependent Enzymes or Thiamine Transport |
| title_sort | posttranslational acylations of the rat brain transketolase discriminate the enzyme responses to inhibitors of thdp dependent enzymes or thiamine transport |
| topic | transketolase malonylation acetylation sirtuin 5 oxythiamine metformin |
| url | https://www.mdpi.com/1422-0067/25/2/917 |
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