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Unraveling mTOR signaling: from two complexes to nuclear dynamics (786.1)
Author(s) -
Sarbassov Dos
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.786.1
Subject(s) - mtorc2 , mtorc1 , pi3k/akt/mtor pathway , ribosome biogenesis , ribosomal protein , microbiology and biotechnology , ribosomal rna , rptor , ribosome , biology , nuclear export signal , nucleoporin , nuclear transport , nuclear pore , cytosol , cell nucleus , signal transduction , biochemistry , gene , rna , enzyme , cytoplasm
The protein kinase mTOR is a central component of the essential and highly conserved nutrient‐sensing pathway. Our biochemical characterization of mTOR led to discovery of a novel nuclear envelope mTOR complex that is distinct from the known complexes of mTOR (mTORC1 and mTORC2) by size and also by the sub‐cellular localization. We found that mTOR in association with the nuclear pore component forms the nuclear envelope complex that regulates the nutrient‐dependent nuclear import of ribosomal proteins. We found that similar to the amino acid deprivation, the mTOR kinase inhibitors caused a substantial decrease in abundance of ribosomal proteins in the nuclear but not cytosolic fraction. The mTOR‐dependent nuclear import of ribosomal proteins is also supported by analysis of the GFP‐tagged ribosomal protein in the cell based imaging assays. The nuclear abundance of ribosomal proteins was not affected by inhibition of mTORC1 by rapamycin or loss of mTORC2. Thus, our study identified a novel role of mTOR in regulation of the nuclear import of ribosomal proteins that might play a role in ribosomal biogenesis and contribute to the nutrient‐dependent regulation of cell growth. Grant Funding Source : Supported by Texas State (CPRIT)