Functions as an intracellular glutamine sensor that directly activates the TORC1 signaling pathway, to promote cell growth when glutamine is available (PubMed:34535752, PubMed:29698392, PubMed:28483912, PubMed:26510498, PubMed:32801125). May play a role in repressing NPR1 activity independently of TORC1 signaling (By similarity). Activated by glutamine (PubMed:34535752, PubMed:29698392). May also be activated by cysteine (PubMed:34535752). Interacts with the TORC1 complex when activated by glutamine or cysteine (PubMed:34535752, PubMed:29698392, PubMed:28483912). Interacts with TOR1; glutamine enhances the interaction (PubMed:34535752, PubMed:29698392, PubMed:28483912). Interacts with KOG1; glutamine enhances the interaction (PubMed:29698392). Interacts with TCO89 (PubMed:29698392). Interacts with LST8; glutamine enhances the interaction (PubMed:29698392). Interacts with TOR2; glutamine enhances the interaction (PubMed:29698392). The FYVE-type zinc finger domain contributes to vacuolar localization. Abnormal activation of TORC1 signaling in nitrogen-replete conditions (glutamine nitrogen source), and during high hydrostatic pressure (mechanical stress) (PubMed:29698392, PubMed:28483912, PubMed:32801125). Increases cellular levels of glutamine and alanine during high hydrostatic pressure (mechanical stress) (PubMed:32801125). Sensitive to rapamycin (TORC1 signaling-inhibitor), caffeine, and high hydrostatic pressure (mechanical stress) (PubMed:29698392, PubMed:34535752, PubMed:26510498, PubMed:32801125). Resistance to tunicamycin (endoplasmic reticulum stressor) administered together with FK506 (calcineurin inhibitor) (PubMed:26510498). Localization of TORC1 to vacuoles is normal (PubMed:28483912). Simultaneous disruption of GTR1 results in TOR1 mislocalization and loss of TORC1 activity and viability (PubMed:29698392). Simultaneous disruption of EGO1 results in loss of viability (PubMed:29698392).