The splicing-factor oncoprotein SF2/ASF activates mTORC1

Karni, R., Hippo, Y., Lowe, S. W., Krainer, A. R. (October 2008) The splicing-factor oncoprotein SF2/ASF activates mTORC1. Proc Natl Acad Sci U S A, 105 (40). pp. 15323-7.

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URL: http://www.ncbi.nlm.nih.gov/pubmed/18832178
DOI: 10.1073/pnas.0801376105

Abstract

The splicing factor SF2/ASF is an oncoprotein that is up-regulated in many cancers and can transform immortal rodent fibroblasts when slightly overexpressed. The mTOR signaling pathway is activated in many cancers, and pharmacological blockers of this pathway are in clinical trials as anticancer drugs. We examined the activity of the mTOR pathway in cells transformed by SF2/ASF and found that this splicing factor activates the mTORC1 branch of the pathway, as measured by S6K and eIF4EBP1 phosphorylation. This activation is specific to mTORC1 because no activation of Akt, an mTORC2 substrate, was detected. mTORC1 activation by SF2/ASF bypasses upstream PI3K/Akt signaling and is essential for SF2/ASF-mediated transformation, as inhibition of mTOR by rapamycin blocked transformation by SF2/ASF in vitro and in vivo. Moreover, shRNA-mediated knockdown of mTOR, or of the specific mTORC1 and mTORC2 components Raptor and Rictor, abolished the tumorigenic potential of cells overexpressing SF2/ASF. These results suggest that clinical tumors with SF2/ASF up-regulation could be especially sensitive to mTOR inhibitors.

Item Type: Paper
Uncontrolled Keywords: alternative splicing mTOR Raptor transformation rapamycin
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > splicing factor
CSHL Authors:
Communities: CSHL labs > Krainer lab
CSHL labs > Lowe lab
Depositing User: Matt Covey
Date: 7 October 2008
Date Deposited: 22 Feb 2013 21:41
Last Modified: 08 Nov 2017 21:01
PMCID: PMC2563124
Related URLs:
URI: http://repository.cshl.edu/id/eprint/27625

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