Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 20 March 2001
Vol. 2001, Issue 74, p. tw5
[DOI: 10.1126/stke.2001.74.tw5]

EDITORS' CHOICE

Transcription An I{kappa}B Sink

The transcription factor NF-{kappa}B has critical functions in control of immune and inflammatory responses (see STKE Review by Rothwarf and Karin). The required strict control of NF-{kappa}B transcriptional activity is mediated in part by inhibitory I{kappa}B proteins. When the I{kappa}B proteins are degraded, NF-{kappa}B activity is increased. I{kappa}B proteins appear to act in multiple ways to hold NF-{kappa}B activity in check. When it interacts with NF-{kappa}B, I{kappa}Bα appears to hide the nuclear localization sequence of the NF-{kappa}B Rel subunit and also to inhibit DNA binding by NF-{kappa}B. I{kappa}Bα also moves between the cytoplasm and nucleus through the actions of a nuclear localization sequence and a nuclear export sequence that interacts with the importin protein CRM1. Such nuclear export may also carry NF-{kappa}B-I{kappa}B complexes out of the nucleus and contribute to transcriptional control. Tam and Sen now report that the regulatory properties appear to differ in various I{kappa}B family members. In particular, they show that I{kappa}Bβ and I{kappa}B{epsilon} do not shuttle out of the nucleus by CRM1-dependent transport. The authors suggest that, rather than facilitating nuclear export of NF-{kappa}B, I{kappa}Bβ and I{kappa}B{epsilon} function primarily by sequestration of NF-{kappa}B in the cytoplasm.

W. F. Tam, R. Sen, I{kappa}B family members function by different mechanisms. J. Biol. Chem. 276, 7701-7704 (2001). [Abstract] [Full Text]

Citation: An I{kappa}B Sink. Sci. STKE 2001, tw5 (2001).


To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882