IndraLab
Statements
"Mtorc1 promotes protein synthesis by phosphorylating the eukaryotic initiation factor 4e (eif4e)- binding protein 1 (4e-bp1) and the p70 ribosomal s6 kinase 1 (s6k1). Raft1 phosphorylation of 4e-bp1 on thr-36 and thr-45 blocks its association with the cap-binding protein, eif-4e,in vitro. in response to insulin and nutrients, mtorc1, consisting of mtor, raptor (regulatory-associated protein of mtor), and mlst8, is activated and phosphorylates eukaryotic initiation factor 4e-binding protein (4ebp) and p70 s6 kinase to promote protein synthesis and cell size."
"Specifically as part of mTORC1, mTOR directly phosphorylates the ribo- somal protein S6 kinases (S6K1 and S6K2) and the eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BP1 and 4E-BP2), both of which control specific steps in the initiation of cap-dependent translation"
rlimsp
"Both (S/T)P sites, such as Thr36, Thr45, and Thr69 in PHAS-I and the h(S/T)h site (where h is a hydrophobic amino acid) Thr389 in p70(S6K), were phosphorylated. Rapamycin-FKBP12 inhibited mTOR activity. Surprisingly, the extent of inhibition depended on the substrate. Moreover, mutating Ser2035 in the rapamycin-binding domain (FRB) not only decreased rapamycin sensitivity as expected but also dramatically affected the sites phosphorylated by mTOR."
rlimsp
"We also measured the phosphorylation of the T36/45 residues on 4E-BP1. Importantly, numerous studies have shown that mTOR can directly phosphorylate these residues [42], [43], but much to our surprise, neither mechanical stimulation, nor U0126, altered the amount of T36/45 phosphorylation."