Journal Article

Functional Study of the Hap4-Like Genes Suggests That the Key Regulators of Carbon Metabolism HAP4 and Oxidative Stress Response YAP1 in Yeast Diverged from a Common Ancestor

Stasyk, Oleh V., Delacroix, Hervé, Bolotin-Fukuhara, Monique, Zhou, You-Fang, Bao, Wei-Guo, Imbeaud, Sandrine, Coudouel, Sophie, Sybirna, Kateryna, Guiard, Bernard, Stasyk, Olena G., Petryk, Nataliya, Budin, Karine, Mucchielli, Marie-Hélène, Krasovska, Olena S., Reymond, Nancie, Sibirny, Andriy

2014

Overview

The transcriptional regulator HAP4, induced by respiratory substrates, is involved in the balance between fermentation and respiration in S. cerevisiae. We identified putative orthologues of the Hap4 protein in all ascomycetes, based only on a conserved sixteen amino acid-long motif. In addition to this motif, some of these proteins contain a DNA-binding motif of the bZIP type, while being nonetheless globally highly divergent. The genome of the yeast Hansenula polymorpha contains two HAP4-like genes encoding the protein HpHap4-A which, like ScHap4, is devoid of a bZIP motif, and HpHap4-B which contains it. This species has been chosen for a detailed examination of their respective properties. Based mostly on global gene expression studies performed in the S. cerevisiae HAP4 disruption mutant (ScΔhap4), we show here that HpHap4-A is functionally equivalent to ScHap4, whereas HpHap4-B is not. Moreover HpHAP4-B is able to complement the H2O2 hypersensitivity of the ScYap1 deletant, YAP1 being, in S. cerevisiae, the main regulator of oxidative stress. Finally, a transcriptomic analysis performed in the ScΔyap1 strain overexpressing HpHAP4-B shows that HpHap4-B acts both on oxidative stress response and carbohydrate metabolism in a manner different from both ScYap1 and ScHap4. Deletion of these two genes in their natural host, H. polymorpha, confirms that HpHAP4-A participates in the control of the fermentation/respiration balance, while HpHAP4-B is involved in oxidative stress since its deletion leads to hypersensitivity to H2O2. These data, placed in an evolutionary context, raise new questions concerning the evolution of the HAP4 transcriptional regulation function and suggest that Yap1 and Hap4 have diverged from a unique regulatory protein in the fungal ancestor.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Amino Acid Motifs - genetics / Amino acids / Analysis / Baking yeast / Biology / Biology and Life Sciences / Carbohydrate metabolism / Carbohydrates / Carbon - metabolism / CCAAT-Binding Factor - genetics / CCAAT-Binding Factor - metabolism / Cellular stress response / Deoxyribonucleic acid / DNA / Evolution / Fermentation / Gene expression / Gene Expression Regulation, Fungal / Gene regulation / Genes / Genome, Fungal / Genomes / Genomics / Hansenula / Hap4 protein / Hydrogen peroxide / Hydrogen Peroxide - chemistry / Hypersensitivity / Kluyveromyces lactis / Life Sciences / Metabolism / Oxidation-Reduction / Oxidative metabolism / Oxidative stress / Oxidative Stress - genetics / Phylogenetics / Protein binding / Proteins / Respiration / Saccharomyces cerevisiae / Saccharomyces cerevisiae - genetics / Saccharomyces cerevisiae Proteins - genetics / Saccharomyces cerevisiae Proteins - metabolism / Stress response / Substrates / Transcription / Transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / Transcription, Genetic / Yeast / Yes-associated protein