General amino-acid permease involved in the uptake of all the naturally occurring L-amino-acids, related compounds such as ornithine and citrulline, some D-amino acids, toxic amino acid analogs such as azetidine-2-carboxylate, and the polyamines putrescine and spermidine (PubMed:5474888, PubMed:10467005, PubMed:10373490, PubMed:10953083, PubMed:14968425, PubMed:15707981). Senses its transport substrates to set an appropriate level of transporter activity at the cell surface (PubMed:21471002). Required for FLO11 expression and invasive growth (PubMed:22844449). Depending on nitrogen source, GAP1 is transported to the plasma membrane, where it functions for amino acid uptake, or to the vacuole, where it is degraded (PubMed:11500494, PubMed:11352928, PubMed:12499351, PubMed:12417748, PubMed:14523026, PubMed:15039776, PubMed:21471002). Expression is repressed by ammonia (PubMed:2194797). Expression is induced by polyamines (PubMed:15707981). Both GLN3 and NIL1 bind the 5'-GATAAG-3' motif within the GAP1 promoter to activate transcription (PubMed:8636059). Active permease is phosphorylated (PubMed:7798155). The addition of glutamine causes rapid dephosphorylation and inactivation of the permease (PubMed:7798155). Ubiquitination by RSP5 and the RSP5-associated proteins BUL1 and BUL2, leads the addition of poly-ubiquitin chains being specifically formed by linkage through the lysine 63 residue of ubiquitin and mediates ammonium-induced endocytosis and degradation in the vacuole (PubMed:9614172, PubMed:10194416, PubMed:11500494, PubMed:11352928, PubMed:14523026, PubMed:15039776). Belongs to the amino acid-polyamine-organocation (APC) superfamily. YAT (TC 2.A.3.10) family.