PIK-related protein kinase and rapamycin target; subunit of TORC1, a complex that controls growth in response to nutrients by regulating translation, transcription, ribosome biogenesis, nutrient transport and autophagy; involved in meiosis; indole-3-acetic acid, an ATP-competitive inhibitor of TORC1, accumulates upon entry into stationary phase; TOR1 has a paralog, TOR2, that arose from the whole genome duplication