Shigeki Miyamoto, PhD

Research Interests

Our laboratory studies regulation of the transcription factor NF-kB as a model system to learn how normal growth control and cell death are regulated and how deregulation of such processes may contribute to development of cancer. NF-kB is normally sequestered in the cytoplasm by an inhibitor protein, IkB. A variety of extracellular signals induce rapid release of IkB from NF-kB, thereby allowing nuclear translocation of NF-kB to activate target gene expression. The products of these NF-kB target genes regulate diverse biological processes, including immune function, growth control and apoptosis. We are currently investigating the following three specific areas of research:

• What is the mechanism and consequence of NF-kB activation by nuclear DNA damage? Activation of cytoplasmically localized NF-kB by DNA damaging agents suggests that DNA-damage in the nucleus may generate a signal that is transduced out to the cytoplasm–the reverse of classical NF-kB activation pathways. We are investigating the components and biochemical processes involved in this signaling pathway using DNA damaging anti-cancer agents (i.e., ionizing radiation and topoisomerase I and II inhibitors). We are also investigating the potential utility of this pathway in enhancing current methods of anti-cancer treatments.
• What is the mechanism of constitutive NF-kB activation during B cell development and in human cancers? We have recently discovered a novel mechanism of IkB degradation involved in constitutive NF-kB activation. We are looking to identify the IkB protease and its regulatory pathways during B cell development and in human cancer cells.
• How is the localization of inactive NF-kB/IkB complexes regulated? We have shown that dominant nuclear export over weaker nuclear import maintains inactive NF-kB/IkBacomplexes in the cytoplasm. We are currently investigating the regulatory mechanisms involved in this process and biological consequences when this novel NF-kB regulatory mechanism is disrupted.

Honors & Awards

• H.I. Romnes Faculty Fellow