can1

CAn1 is the gene CAN1 from the budding yeast Saccharomyces cerevisiae. The protein it encodes, Can1p, is a plasma membrane transporter that mediates uptake of basic amino acids, especially arginine, and also imports the toxic arginine analog canavanine. It belongs to the amino acid permease family and functions as a high-affinity transporter under certain nitrogen conditions.

Can1p activity and localization are regulated by nitrogen availability and substrate presence. In many strains, Can1p resides at the plasma membrane but can be internalized and degraded via ubiquitination in response to arginine or canavanine exposure, a form of substrate-induced downregulation that helps control intracellular arginine levels. The expression of CAN1 is modulated by nitrogen catabolite repression and growth conditions, aligning uptake with cellular nitrogen status.

CAN1 mutations confer resistance to canavanine, allowing the use of canavanine-containing media as a selection method in yeast genetics. CAN1 and its protein product have been studied as a model for transporter regulation, membrane trafficking, and amino acid transport in eukaryotes. Homologs or functionally related transporters are found in other fungi, reflecting conserved roles in amino acid uptake.