▁of ▁signals , ▁including ▁growth ▁factors , ▁nut ri ents , ▁and ▁stress ▁conditions , ▁to ▁reg ulate ▁cell ▁growth ▁and ▁cell ▁size . ▁ ▁Two ▁distinct ▁T OR ▁complex es , ▁T OR C 1 ▁and ▁T OR C 2 , ▁have ▁been ▁identified . ▁These ▁two ▁T OR ▁complex es ▁ph osph ory late ▁different ▁substr ates ▁and ▁have ▁distinct ▁phys i ological ▁functions . ▁For ▁example , ▁T OR C 1 ▁ph osph ory l ates ▁the ▁rib os om al ▁S 6 ▁kin ase ▁( S 6 K ), ▁thereby ▁reg ulating ▁translation ▁and ▁cell ▁growth . ▁ ▁In ▁contrast , ▁T OR C 2 ▁ph osph ory l ates ▁and ▁activ ates ▁A K T , ▁a ▁key ▁kin ase ▁involved ▁in ▁cell ▁growth ▁and ▁apo pt osis . ▁Gu an ▁and ▁his ▁team ▁are ▁interested ▁in ▁how ▁m T OR ▁is ▁reg ulated ▁by ▁up stream ▁signals , ▁such ▁nut ri ents ▁and ▁cell ular ▁energy ▁levels . ▁In ▁addition , ▁they ▁are ▁studying ▁the ▁mechanism ▁of ▁m T OR ▁activation ▁by ▁the ▁ph osph at id yl ▁in os it ol ▁ 3 - kin ase ▁( PI 3 K ). ▁ ▁The ▁second ▁project ▁in ▁his ▁labor atory ▁is ▁studying ▁the ▁novel ▁Hi ppo ▁tum or ▁suppress or ▁path way . ▁Rec ent ▁gen etic ▁studies ▁in ▁D ros oph ila ▁have ▁shown ▁that ▁the ▁Hi ppo ▁signal ing ▁path way ▁plays ▁a ▁key ▁role ▁in ▁restrict ing ▁organ ▁size ▁by ▁cont rolling ▁both ▁cell