regulatory-associated protein of mTOR; Raptor; P150 target of rapamycin (TOR)-scaffold protein (RPTOR, KIAA1303)

Function: - role in the FRAP1 (mTOR) pathway & thus the rate of cell growth & maintenance of cell size with different environmental conditions - complexes with mTOR, negatively regulating mTOR kinase activity via a nutrient-sensitive complex - role as a scaffold protein in the FRAP1-signaling pathway; interaction is essential for phosphorylation of EIF4EBP1 - positive role in nutrient-stimulated signaling to the downstream effector RPS6KB1 - under nutrient-deprived conditions, serves as a negative regulator of FRAP1 kinase activity - binds directly 4EBP1 & RPS6KB1 independently of its association with FRAP1 - binds preferentially to poorly or non-phosphorylated form of EIF4EBP1, & this binding is critical to the ability of FRAP1 to catalyze phosphorylation - complex with FRAP1 physically interacts under both leucine-rich & -poor conditions & therefore in at least two nutrient-determined states with different stability Structure: - belongs to the WD repeat RAPTOR family - contains 7 WD repeats Alternative splicing: named isoforms=2 Expression: - highly expressed in skeletal muscle - expressed to lesser extent in brain, lung, small intestine, kidney & placenta Notes: - rapamycin destabilizes the interaction with FRAP1 regardless of nutrient availability, & its potency for dissociation is increased under nutrient-rich conditions; this action uncouples FRAP1 from its substrates, & inhibits FRAP1 signaling without altering its intrinsic catalytic activity

General

phosphoprotein WD repeat protein family

Properties

SIZE: entity length = 1335 aa MW = 149 kD MOTIF: Ser phosphorylation site {S719} Ser phosphorylation site {S722} Thr phosphorylation site {T857} Ser phosphorylation site {S859} Ser phosphorylation site {S863} Thr phosphorylation site {T865} Ser phosphorylation site {S877} serine-rich region {881-887} MOTIF: serine residue (SEVERAL) WD repeat {1020-1061} WD repeat {1065-1106} WD repeat {1121-1160} WD repeat {1164-1203} WD repeat {1209-1249} WD repeat {1251-1291} WD repeat {1299-1335}

Database Correlations

OMIM 607130 UniProt Q8N122 Pfam PF02985 Entrez Gene 57521 Kegg hsa:57521