EIF4EBP1 and mucopolysaccharidosis: In MPS, the mechanistic target of the rapamycin complex 1 (mTORC1)-mediated phosphorylation of its downstream factor p70 ribosomal protein S6 kinase (p70S6K) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) promotes protein synthesis [18].