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 #
5R01CA089640-25
Application #
7668032
Study Section
Special Emphasis Panel (ZRG1-ONC-U (90))
Program Officer
Spalholz, Barbara A
Project Start
2001-02-01
Project End
2010-07-31
Budget Start
2009-08-01
Budget End
2010-07-31
Support Year
25
Fiscal Year
2009
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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