The type 1 insulin-like growth factor receptor (IGF-IR) has recently become one of the favorite targets of industry for its possible role in the growth of normal and abnormal cells. IGF-IR signaling also plays a significant role in longevity, from C. elegans to mammalians. The IGF axis controls, in a non-redundant way, about 50% of growth in animals and cells in culture, largely through the activation of its docking protein, the insulin receptor substrate-1 (IRS-1). Deletion of IRS-1 (or its homologues in Drosophila) results in animals or cells that are roughly 50% in size. We have recently found that IRS-1 translocates to the nuclei where it binds and activates UBF1 (Upstream Binding Factor 1), a protein that regulates RNA polymerase I activity, and therefore cell (and body) size. In this application, we propose to study: 1) the mechanism by which IRS-1 regulates the activity and/or the stability of UBF1; 2) the mechanism(s) by which nuclear IRS-1 competes with other nucleolar proteins for the activation of the ribosomal DNA promoter; and 3) the physical and biological interactions of IRS-1 with the SV40 T antigen and selected RNA polymerase-2-directed promoters n the nuclei of cells, an interaction that may be critical for the transformation of cells. These studies have a direct impact on our basic knowledge of the biology of cancer and may throw light on mechanisms of aging. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA089640-24
Application #
7483621
Study Section
Special Emphasis Panel (ZRG1-ONC-U (90))
Program Officer
Lei, Ming
Project Start
2001-02-01
Project End
2010-07-31
Budget Start
2008-08-01
Budget End
2009-07-31
Support Year
24
Fiscal Year
2008
Total Cost
$210,180
Indirect Cost
Name
Thomas Jefferson University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
053284659
City
Philadelphia
State
PA
Country
United States
Zip Code
19107
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