High impact information on HXT5

• Our results showed that recombinant RE700A containing the cloned HXT7 or HXT5 were substantially more effective for fermenting xylose to ethanol [1].
• The PDS element and, to a lesser extent, the other STRE showed particular involvement in regulation of HXT5 expression during growth on ethanol [2].
• A possible mechanism by which expression of HXT5 could be regulated by the transcriptional regulatory elements in the promoter is discussed [2].
• Because gene expression is regulated by binding of specific transcription factors to regulatory elements in the promoters of genes, the presence of putative regulatory elements in the promoter of HXT5 was determined by computer-assisted analysis [2].
• In glucose-grown batch cultures, HXT5 is expressed prior to glucose depletion [3].

Biological context of HXT5

• Determination of in vivo kinetics of the starvation-induced Hxt5 glucose transporter of Saccharomyces cerevisiae [4].
• The deletion of HXT5 does not result in a clear phenotype [5].
• The sole presence of Hxt5p in an otherwise hexose transport null mutant is sufficient to sustain a flux through glycolysis from glucose to fermentative products [5].
• Addition of glucose to stationary-phase cells resulted in a transient phosphorylation of Hxt5p on serine residues, but no ubiquitination was detected [6].
• Hxt5p is a member of a multigene family of hexose transporter proteins which translocate glucose across the plasma membrane of the yeast Saccharomyces cerevisiae [6].

Anatomical context of HXT5

• These results suggest that internalization and degradation of Hxt5p in the vacuole occur in an ubiquitination-independent manner via the endocytic pathway [6].

Associations of HXT5 with chemical compounds

• The HXT5 gene was not expressed during growth of the yeast cells in rich medium with glucose or raffinose [4].
• The HXT5 gene encodes a functional hexose transporter that has moderate affinity for glucose (K(m)=10 mM), moderate to low affinity for fructose (K(m)=40 mM) and low affinity for mannose (K(m)>100 mM) [5].
• Independent of the carbon source used in batch cultures, HXT5 is expressed after 24 h of growth and during growth on ethanol or glycerol, which indicates that growth on glucose is not necessary for expression of HXT5 [3].

Analytical, diagnostic and therapeutic context of HXT5

• From Northern blot analysis on the members of the HXT family and studies with HXT5 tagged with the green fluorescent protein (GFP), it is evident that HXT5 is transcribed and translated during conditions of relatively slow growth, during growth on non-fermentable carbon sources and in particular during sporulation [5].
• The decrease in Hxt5p levels is caused by internalization of the protein, as observed by immunofluorescence microscopy [6].
• Electron microscopy demonstrated that the internalized Hxt5p-HA (haemagglutinin) protein was localized to small vesicles, multivesicular bodies and the vacuole [6].

References