HTLV-I Tax induces the aberrant expression of various growth related cellular genes by activating the NFkappaB/Rel transcription factors. Recent studies demonstrate that Tax activation of NF-kappaB/Rel is associated with the proteolytic degradation of IkappaB-alpha and IkappaB- beta, two major cytoplasmic inhibitors of NF-kappaB. The overall objective of this proposal is to explore the biochemical mechanisms underlying Tax- induced phosphorylaiton and degradation of I,kappaB-alpha as well as the inactivation of IkappaB-beta.
The specific aims are twofold; (i) to identify and functionally characterize IkappaB-alpha protein kinases; (ii) to explore the mechanism by which Tax induces the degradation of IkappaB- beta. The IkappaB-alpha specific protein kinases will be isolated by goth biochemical and genetic (yeast two hybrid system) approaches. The isolated candidate IkappaB-alpha kinases will be characterized by both in vitro kinase assays and in vivo functional analyses. In addition, the expression pattern of the kinases in HTLV-I-infected and normal T cells will be investigated by Northern analysis. To investigate how Tax induces the degradation of IkappaB-beta, phosphopeptide mapping coupled with site directed mutagenesis will be initially performed to determine whether phosphorylation is required for Tax-induced IkappaB-beta degradation. Additionally, progressive deletions will be introduced to 1kappaB-beta to completely define the sequences within IkappaB-beta that are involved in the Tax-mediated inactivation of this inhibitor. Together, these proposed experimental approaches should provide important insights into early steps of the development of ATL.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32CA071108-02
Application #
2458259
Study Section
Experimental Virology Study Section (EVR)
Project Start
1997-08-01
Project End
Budget Start
1997-08-01
Budget End
1998-01-09
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Pennsylvania State University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
129348186
City
Hershey
State
PA
Country
United States
Zip Code
17033