Human mTOR is a 2549 amino acid protein. It contains multiple HEAT repeats, a helix turn helix (HTH) motif, and a Golgi/ER localization signal sequence (LS) at its N-terminus. Its catalytic domain is flanked by a FAT and FATC sequences. Immediate upstream to the catalytic domain is the FKBP12-rapamycin binding (FRB) motif. A phosphomimetic residue Asp (E2363) at its putative activation loop, three known phosphorylation sites, T2446, S2448, and S2481, and three other less characterized phosphorylation sites, S1261, S2159, T2164, are shown.