Ure2
Ure2, or Ure2p, is a yeast protein encoded by a gene known as URE2 (systematic designation YNL229C). The Ure2 protein can also form a yeast prion known as [URE3].[1] When Ura2p is expressed at high levels in yeast, it will readily convert from its native protein conformation into an aggregate known as an amyloid. [URE3], along with [PSI+], were both determined by Wickner (1994) to meet the genetic definition of a yeast prion.
The gene prefix "URE" stands for ureidosuccinate transport, as the Ure2 protein in its native state is responsible for repressing nitrogen catabolism of glutamine by controlling the GLN3 transcription factor. Gln3p is retained in the cytoplasm by Ure2p when a preferred nitrogen source like ammonium sulfate is present in the growth media, but enters the nucleus when the cells are shifted to a nonpreferred source of nitrogen such as proline.[2] Ure2 protein also plays a role in responding to oxidative stress.[3]
Ure2p is a protein composed of 354 amino acids and has a molecular weight of 40,226. Its gene, URE2, been mapped to chromosome XIV, 5 map units from KEX2.[4]
References
- ^ Wickner, R.B. (1994). "[URE3] as an altered URE2 protein: Evidence for a prion analog in Saccharomyces cerevisiae". Science. 264 (5158): 566–569. doi:10.1126/science.7909170. PMID 7909170.
- ^ Magasanik, B. (2005). "The transduction of the nitrogen regulation signal in Saccharomyces cerevisiae". Proc. Natl. Acad. Sci. USA. 102 (46): 16537–16538. doi:10.1073/pnas.0507116102. PMC 1283824. PMID 16275904.
- ^ Rai, R and; Cooper, T.G. (2005). "In vivo specificity of Ure2 protection from heavy metal ion and oxidative cellular damage in Saccharomyces cerevisiae". Yeast. 22 (5): 343–58. doi:10.1002/yea.1215. PMC 4383137. PMID 15806612.
- ^ Coschigano, P.W.; Magasanik, B. (February 1991). "The URE2 gene product of Saccharomyces cerevisiae plays an important role in the cellular response to the nitrogen source and has homology to glutathione s-transferases". Molecular and Cellular Biology. 11 (2).