- THIS ARTICLE
- Full Text
- Full Text (PDF)
- Supporting Information
-
All Versions of this Article:
genetics.109.103747v1
183/4/1327 most recent - Alert me when this article is cited
- Alert me if a correction is posted
- SERVICES
- Email this article to a friend
- Similar articles in this journal
- Similar articles in PubMed
- Alert me to new issues of the journal
- Download to citation manager
- Reprints & Permissions
- CITING ARTICLES
- Citing Articles via HighWire
- GOOGLE SCHOLAR
- Articles by Inwood, W. B.
- Articles by Kustu, S.
- PUBMED
- PubMed Citation
- Articles by Inwood, W. B.
- Articles by Kustu, S.
Originally published as Genetics Published Articles Ahead of Print on July 13, 2009.
Genetics, Vol. 183, 1327-1340, December 2009, Copyright © 2009
doi:10.1534/genetics.109.103747
Epistatic Effects of the Protease/Chaperone HflB on Some Damaged Forms of the Escherichia coli Ammonium Channel AmtB
William B. Inwood, Jason A. Hall, Kwang-Seo Kim, Lusine Demirkhanyan1, David Wemmer2, Helen Zgurskaya1 and Sydney Kustu3
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
3 Corresponding author: Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720-3102.
E-mail: kustu{at}berkeley.edu
The Escherichia coli ammonium channel AmtB is a trimer in which each monomer carries a pore for substrate conduction and a cytoplasmic C-terminal extension of 
25 residues. Deletion of the entire extension leaves the protein with intermediate activity, but some smaller lesions in this region completely inactivate AmtB, as do some lesions in its cytoplasmic loops. We here provide genetic evidence that inactivation depends on the essential protease HflB, which appears to cause inactivation not as a protease but as a chaperone. Selection for restored function of AmtB is a positive selection for loss of the ATPase/chaperone activity of HflB and reveals that the conditional lethal phenotype for hflB is cold sensitivity. Deletion of only a few residues from the C terminus of damaged AmtB proteins seems to prevent HflB from acting on them. Either yields the intermediate activity of a complete C-terminal deletion. HflB apparently "tacks" damaged AmtB tails to the adjacent monomers. Knowing that HflB has intervened is prerequisite to determining the functional basis for AmtB inactivation.
This article has been cited by other articles:
 |
|
 |
|
  W. B. Inwood, J. A. Hall, K.-S. Kim, R. Fong, and S. Kustu Genetic Evidence for an Essential Oscillation of Transmembrane-Spanning Segment 5 in the Escherichia coli Ammonium Channel AmtB Genetics, December 1, 2009; 183(4): 1341 - 1355. [Abstract] [Full Text] [PDF]
|
|
|