Component of TORC1, which regulates multiple cellular processes to control cell growth in response to environmental signals. Nutrient limitation and environmental stress signals cause inactivation of TORC1. Active TORC1 positively controls ribosome biogenesis via control of rRNA, ribosomal protein and tRNA gene expression, and rRNA processing. TORC1 positively controls protein biosynthesis by regulation of mRNA stability, translation initiation factor activity, and high-affinity amino acid permeases that serve to provide amino acids for use by the translation machinery. TORC1 also promotes growth by sequestering a number of nutrient and general stress-responsive transcription factors in the cytoplasm. TORC1 negatively controls macroautophagy, a process to recycle surplus cytoplasmic mass under nutrient starvation conditions. KOG1 may have a role in binding and recruiting substrates of TORC1. The target of rapamycin complex 1 (TORC1) is composed of at least KOG1, LST8, TCO89 and either TOR1 (TORC1-A) or TOR2 (TORC1-B) (PubMed:12408816, PubMed:12631735, PubMed:16394584). Interacts with PIB2; following activation of PIB2 by glutamine or cysteine (PubMed:29698392). TORC1 binds to and is inhibited by FKBP-rapamycin (PubMed:12408816). Also localizes to membranous structures within the cell interior, probably endosomal or Golgi membranes. Belongs to the WD repeat RAPTOR family.