Sodium-dependent amino acid transporter that mediates the uptake of the L-enantiomers of various amino acids, including L-proline and L-methionine, and also of acidic amino acids such as L-glutamic acid and L-aspartic acid (PubMed:23580723) (Probable). May additionally have a role in potassium-dependent amino acid absorption (PubMed:23580723). In response to the availability of amino acid nutrients, may play a role in dauer formation (PubMed:23580723). May play a role in promoting fertility (PubMed:30560135). Expressed in the INT-9 cells and posterior cells of the alimentary canal of the intestine, gut epithelial cells, the pharynx of some worms, two cells of the rectal gland, and in DVA, DVB and DVC neurons and amphid sensory neurons ASI, ADF and ASK neurons. Impaired capacity to form and maintain dauer larvae upon starvation (PubMed:23580723). RNAi-mediated knockdown in a pept-1 (lg601) mutant background results in a reduced number of progeny (PubMed:30560135). Dietary supplementation with glutamate does not rescue this phenotype (PubMed:30560135). Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family.