Simplified model of leucine-, insulin/IGF-1-, and glucose-dependent activation of mTORC1; Akt: Akt kinase; AMPK: AMP-activated protein kinase; ATP: adenosine triphosphate; 4E-BP1: eukaryotic initiation factor (eIF) 4E-binding protein 1; GLUT: glucose transporter protein; IGF-1: insulin-like growth factor 1; IGF1R: IGF-1 receptor; IR: insulin receptor; IRS-1: insulin receptor substrate 1; LAT: L-type amino acid transporter; mTORC1: mammalian target of rapamycin complex 1; PI3K: phosphoinositol-3 kinase; Rheb: ras homolog enriched in brain; S6K1: p70 S6 kinase 1; SREBP: sterol regulatory element-binding transcription factor; TSC1: tuberous sclerosis complex 1 (hamartin); TSC2: tuberous sclerosis complex 2 (tuberin).