A double role of the Gal80 N terminus in activation of transcription by Gal4p
| Autor: | Karin D. Breunig, Constance Roehl, Annekathrin Reinhardt-Tews, Christian Günzel, Rościsław Krutyhołowa, Sebastian Glatt |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Transcriptional Activation
Saccharomyces cerevisiae Proteins Health Toxicology and Mutagenesis Saccharomyces cerevisiae Plant Science Biochemistry Genetics and Molecular Biology (miscellaneous) 03 medical and health sciences Galactokinase Kluyveromyces Transcription (biology) Transcriptional regulation NLS Research Articles 030304 developmental biology chemistry.chemical_classification Kluyveromyces lactis Cell Nucleus 0303 health sciences Ecology biology 030302 biochemistry & molecular biology Galactose biology.organism_classification Cell biology N-terminus DNA-Binding Proteins Repressor Proteins Enzyme chemistry Research Article Transcription Factors |
| Zdroj: | Life Science Alliance |
| ISSN: | 2575-1077 |
| Popis: | Activation of gene expression by Gal4p in K. lactis requires an element in the N terminus of KlGal80p that mediates nuclear co-import of KlGal1p and galactokinase inhibition to support the co-inducer function of KlGal1p. The yeast galactose switch operated by the Gal4p–Gal80p–Gal3p regulatory module is a textbook model of transcription regulation in eukaryotes. The Gal80 protein inhibits Gal4p-mediated transcription activation by binding to the transcription activation domain. In Saccharomyces cerevisiae, inhibition is relieved by formation of an alternative Gal80–Gal3 complex. In yeasts lacking a Gal3p ortholog, such as Kluyveromyces lactis, the Gal1 protein (KlGal1p) combines regulatory and enzymatic activity. The data presented here reveal a yet unknown role of the KlGal80 N terminus in the mechanism of Gal4p activation. The N terminus contains an NLS, which is responsible for nuclear accumulation of KlGal80p and KlGal1p and for KlGal80p-mediated galactokinase inhibition. Herein, we present a model where the N terminus of KlGal80p reaches the catalytic center of KlGal1p causing enzyme inhibition in the nucleus and stabilization of the KlGal1–KlGal80p complex. We corroborate this model by genetic analyses and structural modelling and provide a rationale for the divergent evolution of the mechanism activating Gal4p. |
| Databáze: | OpenAIRE |
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