<p>URE2 is a yeast protein that plays an important role in the regulation of nitrogen metabolism [<cite idref="PUB00043594"/>]. When easily utilised nitrogen sources are present, yeast cells down-regulate the synthesis of proteins involved in utilising poor nitrogen sources. URE2 assists this process by interacting with, and repressing, the transcription factor Gln3, repressing the transcription of these proteins. URE2 exists in two forms; a functional form and an infectious, non-functional prion form. Structurally, URE2 is a homodimer where each monomer has a globular C-terminal region, and a poorly structured N-terminal region [<cite idref="PUB00043595"/>, <cite idref="PUB00025148"/>]. The globular region, which is sufficient for its regulatory activity, forms a glutathione-S-transferase-like fold. The N-termnial region is known as the prion region and may interact with the globular region to prevent the protein from converting into its prion form. </p> Prion URE2