Raptor (RPTOR) Antibody – Mouse Monoclonal

This gene encodes a component of a signaling pathway that regulates cell growth in response to nutrient and insulin levels. The encoded protein forms a stoichiometric complex with the mTOR kinase, and also associates with eukaryotic initiation factor 4E-binding protein-1 and ribosomal protein S6 kinase. The protein positively regulates the downstream effector ribosomal protein S6 kinase, and negatively regulates the mTOR kinase. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2009]

Raptor: Involved in the control of the mammalian target of rapamycin complex 1 (mTORC1) activity which regulates cell growth and survival, and autophagy in response to nutrient and hormonal signals; functions as a scaffold for recruiting mTORC1 substrates. mTORC1 is activated in response to growth factors or amino acids. Growth factor-stimulated mTORC1 activation involves a AKT1- mediated phosphorylation of TSC1-TSC2, which leads to the activation of the RHEB GTPase that potently activates the protein kinase activity of mTORC1. Amino acid-signaling to mTORC1 requires its relocalization to the lysosomes mediated by the Ragulator complex and the Rag GTPases. Activated mTORC1 up-regulates protein synthesis by phosphorylating key regulators of mRNA translation and ribosome synthesis. mTORC1 phosphorylates EIF4EBP1 and releases it from inhibiting the elongation initiation factor 4E (eiF4E). mTORC1 phosphorylates and activates S6K1 at 'Thr-389', which then promotes protein synthesis by phosphorylating PDCD4 and targeting it for degradation. Interacts with MTOR. Part of the mammalian target of rapamycin complex 1 (mTORC1) which contains MTOR, MLST8, RPTOR, AKT1S1/PRAS40 and DEPTOR. mTORC1 binds to and is inhibited by FKBP12-rapamycin. Binds directly to 4EBP1 and RPS6KB1 independently of its association with MTOR. Binds preferentially to poorly or non-phosphorylated forms of EIF4EBP1, and this binding is critical to the ability of MTOR to catalyze phosphorylation. Forms a complex with MTOR under both leucine-rich and -poor conditions. Interacts with ULK1 in a nutrient-dependent manner; the interaction is reduced during starvation. Interacts (when phosphorylated by AMPK) with 14-3-3 protein, leading to inhibit its activity. Highly expressed in skeletal muscle, and in a lesser extent in brain, lung, small intestine, kidney and placenta. Belongs to the WD repeat RAPTOR family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Adaptor/scaffold

Chromosomal Location of Human Ortholog: 17q25.3

Cellular Component: nucleoplasm; intracellular membrane-bound organelle; cell soma; lysosomal membrane; lysosome; cytoplasm; dendrite; cytosol

Molecular Function: protein binding; protein complex binding; protein kinase binding

Biological Process: cellular response to nutrient levels; TOR signaling pathway; insulin receptor signaling pathway; positive regulation of transcription from RNA polymerase III promoter; positive regulation of endothelial cell proliferation; cell cycle arrest; cell growth; regulation of cell size; positive regulation of TOR signaling pathway