Sugar repression in the methylotrophic yeastHansenula polymorpha studied by using hexokinase-negative, glucokinase-negative and double kinase-negative mutants

Kramarenko, T.; Karp, Helen; Järviste, Aiki; Alamäe, Tiina

doi:10.1007/bf02818721

Cited by 25 publications

(27 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3A and D). It has been previously established that hexose phosphorylation is required for the repression pathway in H. polymorpha (20). Therefore, the intracellular level of the effector hexose as influenced by its uptake rate may determine the strength of the downstream repression signal (e.g., the rate of hexose phosphorylation).…”

Section: Discussionmentioning

confidence: 99%

“…In H. polymorpha (syn. Pichia angusta) (22), an object of this study, hexose phosphorylation activity, either via hexo-or glucokinase, was demonstrated to be essential for catabolite repression (20).…”

mentioning

confidence: 92%

“…Therefore, comprehensive knowledge of the glucose-triggered pathways in this yeast is required to optimize the H. polymorpha expression platform or to construct strains capable of simultaneous utilization of glucose and other sugars derived from lignocellulose. Taking into account the availability of the Hansenula polymorpha full genome sequence (34) and developed versatile molecular techniques, this yeast may further serve as a convenient model for elucidating glucose-sensing pathways in lower eukaryotes (20,45,46). We have previously demonstrated in H. polymorpha, that the Gcr1 protein, which is similar to glucose sensors, is required for efficient glucose transport and glucose repression but not for pexophagy (46).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Identification of Hexose Transporter-Like Sensor HXS1 and Functional Hexose Transporter HXT1 in the Methylotrophic Yeast Hansenula polymorpha

et al. 2008

View full text Add to dashboard Cite

We identified in the methylotrophic yeast Hansenula polymorpha (syn. Pichia angusta) a novel hexose transporter homologue gene, HXS1 (hexose sensor), involved in transcriptional regulation in response to hexoses, and a regular hexose carrier gene, HXT1 (hexose transporter). The Hxs1 protein exhibits the highest degree of primary sequence similarity to the Saccharomyces cerevisiae transporter-like glucose sensors, Snf3 and Rgt2. When heterologously overexpressed in an S. cerevisiae hexose transporter-less mutant, Hxt1, but not Hxs1, restores growth on glucose or fructose, suggesting that Hxs1 is nonfunctional as a carrier. In its native host, HXS1 is expressed at moderately low level and is required for glucose induction of the H. polymorpha functional low-affinity glucose transporter Hxt1. Similarly to other yeast sensors, one conserved amino acid substitution in the Hxs1 sequence (R203K) converts the protein into a constitutively signaling form and the C-terminal region of Hxs1 is essential for its function in hexose sensing. Hxs1 is not required for glucose repression or catabolite inactivation that involves autophagic degradation of peroxisomes. However, HXS1 deficiency leads to significantly impaired transient transcriptional repression in response to fructose, probably due to the stronger defect in transport of this hexose in the hxs1⌬ deletion strain. Our combined results suggest that in the Crabtree-negative yeast H. polymorpha, the single transporter-like sensor Hxs1 mediates signaling in the hexose induction pathway, whereas the rate of hexose uptake affects the strength of catabolite repression.As a favorite carbon substrate, glucose exerts numerous strong and well-coordinated effects on the physiological state of yeast cells. They include gene-specific regulation of transcription and mRNA stability as well as regulation at the posttranslational level: e.g., catabolite inactivation of certain glucoserepressible enzymes (3,13,19). Signaling pathways involved in different glucose effects have been studied mostly in the model yeast Saccharomyces cerevisiae. A number of participating components have been identified, and some have been shown to have conserved functions in other yeast species (for review, see references 12, 36, and 41). Nevertheless, knowledge of glucose-triggered regulatory pathways for Crabtree-negative yeasts (which contrary to S. cerevisiae, are unable to produce ethanol aerobically in the presence of high external glucose concentrations) (11) that primarily rely on respiratory metabolism still remains very limited. In particular, the first stages, how glucose is sensed, and the molecular triggers involved in different pathways are the least understood aspects of these yeast species.Two nontransporting glucose carrier homologues, Snf3 and Rgt2, have been shown to function as glucose sensors in S. cerevisiae in a pathway of transcriptional induction. They differentially regulate expression of the functional hexose transporters in response to extracellular glucose concentration (32). This ...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 92%

mentioning

confidence: 99%

See 1 more Smart Citation

Identification of Hexose Transporter-Like Sensor HXS1 and Functional Hexose Transporter HXT1 in the Methylotrophic Yeast Hansenula polymorpha

et al. 2008

View full text Add to dashboard Cite

show abstract

“…heterologous gene expression, and for basic research on peroxisome biogenesis and degradation (7,10). There are several reports describing H. polymorpha mutants defective in glucose repression (11)(12)(13). Kramarenko et al (11) demonstrated that glucose has to be phosphorylated in order to cause repression in H. polymorpha, and mutants impaired in activities for hexo-or glucokinases are insensitive to repression.…”

mentioning

confidence: 99%

A Hexose Transporter Homologue Controls Glucose Repression in the Methylotrophic Yeast Hansenula polymorpha

Stasyk

Komduur

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Peroxisome biogenesis and synthesis of peroxisomal enzymes in the methylotrophic yeast Hansenula polymorpha are under the strict control of glucose repression. We identified an H. polymorpha glucose catabolite repression gene (HpGCR1) that encodes a hexose transporter homologue. Deficiency in GCR1 leads to a pleiotropic phenotype that includes the constitutive presence of peroxisomes and peroxisomal enzymes in glucose-grown cells. Glucose transport and repression defects in a UV-induced gcr1-2 mutant were found to result from a missense point mutation that substitutes a serine residue (Ser 85 ) with a phenylalanine in the second predicted transmembrane segment of the Gcr1 protein. In addition to glucose, mannose and trehalose fail to repress the peroxisomal enzyme, alcohol oxidase in gcr1-2 cells. A mutant deleted for the GCR1 gene was additionally deficient in fructose repression. Ethanol, sucrose, and maltose continue to repress peroxisomes and peroxisomal enzymes normally and therefore, appear to have GCR1-independent repression mechanisms in H. polymorpha. Among proteins of the hexose transporter family of baker's yeast, Saccharomyces cerevisiae, the amino acid sequence of the H. polymorpha Gcr1 protein shares the highest similarity with a core region of Snf3p, a putative high affinity glucose sensor. Certain features of the phenotype exhibited by gcr1 mutants suggest a regulatory role for Gcr1p in a repression pathway, along with involvement in hexose transport.If provided with a mixture of carbon substrates, yeast preferentially utilizes the one that supports the fastest growth rate. This is achieved by several coordinated regulatory mechanisms of metabolic adaptation. They include: (i) the induction of enzymes involved in the metabolism of a preferred substrate and (ii) repression and/or inactivation of enzymes involved in the metabolism of less preferred carbon sources. Carbon sourcetriggered repression (or catabolite repression) generally affects expression of the corresponding target genes at the transcriptional level. Among co-repressor substrates in Saccharomyces cerevisiae, glucose is best known (for review see Refs. 1 and 2). The main targets of glucose repression in S. cerevisiae are enzymes of gluconeogenesis and the glyoxylate cycle, mitochondrial enzymes involved in oxidative phosphorylation, and enzymes involved in transport and metabolism of alternative carbon substrates, such as galactose, sucrose, and maltose. Despite extensive studies and a growing number of genes known to be involved in glucose repression in this and other species, its actual mechanism, especially in the early stages of sensing and signal transduction, is not fully understood.In methylotrophic yeasts, unique peroxisomal and cytosolic enzymes of methanol metabolism are under strict control of repression by various carbon substrates, e.g. glucose and ethanol (3, 4). Glucose and ethanol also trigger inactivation of peroxisomal enzymes by a process that involves the autophagic degradation of whole peroxisomes by vacuolar prot...

show abstract

“…We checked several diVerent chemical and enzymatic methods for direct determination of ethanol on the plate but all of them appeared to be unsatisfactory. For example, we tried to determine ethanol on plates using "Alcotest" enzymatic kit containing alcohol oxidase, peroxidase and chromogen [6], an enzymatic kit containing NAD-dependent alcohol dehydrogenase, phenazine metosulfate and nitroblue tetrazolium [12], however, for unknown reasons, these approaches were unsuccessful. Therefore, we decided to develop the plate ethanol-assaying method and use it for subsequent isolation of the mutants with altered ability of ethanol production in the medium with xylose.…”

Section: Resultsmentioning

confidence: 99%

Plate ethanol-screening assay for selection of the Pichia stipitis and Hansenula polymorpha yeast mutants with altered capability for xylose alcoholic fermentation

Grabek-Lejko

Ryabova

Oklejewicz

et al. 2006

J Ind Microbiol Biotechnol

View full text Add to dashboard Cite

A new method for the selection of Pichia stipitis and Hansenula polymorpha yeast mutants with altered capability to ferment xylose to ethanol was developed. The method is based on the ability of P. stipitis and H. polymorpha colonies to grow and produce ethanol on agar plates with xylose as the sole carbon and energy source. Secreted ethanol, in contrast to xylose, supports growth of cells of the indicator xylose-negative strains (the wild-type strain of Saccharomyces cerevisiae or Deltaxyl1 mutant of H. polymorpha) mixed with agar medium. The size of the tester culture-growth zone around xylose-grown colonies appeared to be dependent on the amount of secreted ethanol. Mutants with altered (decreased or elevated) ethanol production in xylose medium have been isolated using this method. The mutants exhibited pleiotropic alterations in enzymatic activities of the intermediary xylose metabolism.

show abstract

Sugar repression in the methylotrophic yeastHansenula polymorpha studied by using hexokinase-negative, glucokinase-negative and double kinase-negative mutants

Cited by 25 publications

References 40 publications

Identification of Hexose Transporter-Like Sensor HXS1 and Functional Hexose Transporter HXT1 in the Methylotrophic Yeast Hansenula polymorpha

Identification of Hexose Transporter-Like Sensor HXS1 and Functional Hexose Transporter HXT1 in the Methylotrophic Yeast Hansenula polymorpha

A Hexose Transporter Homologue Controls Glucose Repression in the Methylotrophic Yeast Hansenula polymorpha

Plate ethanol-screening assay for selection of the Pichia stipitis and Hansenula polymorpha yeast mutants with altered capability for xylose alcoholic fermentation

Contact Info

Product

Resources

About