Raptor, a Binding Partner of Target of Rapamycin

Biochem Biophys Res Commun. 2004 Jan 9;313(2):437-41. doi: 10.1016/j.bbrc.2003.07.018.


The mammalian target of rapamycin (mTOR) controls cell growth in response to amino acids and growth factors, in part by regulating p70 S6 kinase alpha (p70 alpha) and eukaryotic initiation factor 4E binding protein 1 (4EBP1). Raptor (regulatory associated protein of mTOR) is a 150 kDa mTOR binding protein that is essential for TOR signaling in vivo and also binds 4EBP1 and p70alpha through their respective TOS (TOR signaling) motifs, a short conserved segment previously shown to be required for amino acid- and mTOR-dependent regulation of these substrates in vivo. Raptor appears to serve as an mTOR scaffold protein, the binding of which to the TOS motif of mTOR substrates is necessary for effective mTOR-catalyzed phosphorylation. Further understanding of regulation of the mTOR-raptor complex in response to the nutritional environment would require identification of the interplay between the mTOR-raptor complex and its upstream effectors such as the protein products of tumor suppressor gene tuberous sclerosis complexes 1 and 2, and the Ras-related small G protein Rheb.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / metabolism
  • Conserved Sequence
  • Humans
  • Molecular Sequence Data
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Proteins / chemistry
  • Proteins / genetics
  • Proteins / metabolism*
  • Regulatory-Associated Protein of mTOR
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • TOR Serine-Threonine Kinases


  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • EIF4EBP1 protein, human
  • Phosphoproteins
  • Proteins
  • RPTOR protein, human
  • Regulatory-Associated Protein of mTOR
  • Protein Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases