This Article Full Text Full Text (PDF) An authors' corrections has been published Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lee, Y.-Y. Articles by Wu, W. F. Search for Related Content PubMed PubMed Citation Articles by Lee, Y.-Y. Articles by Wu, W. F.

Next Article 

Journal of Bacteriology, April 2003, p. 2393-2401, Vol. 185, No. 8
0021-9193/03/$08.00+0     DOI: 10.1128/JB.185.8.2393-2401.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Subunit Oligomerization and Substrate Recognition of the Escherichia coli ClpYQ (HslUV) Protease Implicated by In Vivo Protein-Protein Interactions in the Yeast Two-Hybrid System

Yi-Ying Lee, Chiung-Fang Chang, Chueh-Ling Kuo, Meng-Ching Chen, Chien Hung Yu, Pei-I Lin, and Whi Fin Wu^*

Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan

Received 3 June 2002/ Accepted 17 January 2003

The Escherichia coli ClpYQ (HslUV) is an ATP-dependent protease that consists of an ATPase large subunit with homology to other Clp family ATPases and a peptidase small subunit related to the proteasomal ß-subunits of eukaryotes. Six identical subunits of both ClpY and ClpQ self-assemble into an oligomeric ring, and two rings of each subunit, two ClpQ rings surrounded by single ClpY rings, form a dumbbell shape complex. The ClpYQ protease degrades the cell division inhibitor, SulA, and a positive regulator of capsule transcription, RcsA, as well as RpoH, a heat shock sigma transcription factor. Using the yeast-two hybrid system, we explored the in vivo protein-protein interactions of the individual subunits of the ClpYQ protease involved in self-oligomerization, as well as in recognition of specific substrates. Interactions were detected with ClpQ/ClpQ, ClpQ/ClpY, and ClpY/SulA. No interactions were observed in experiments with ClpY/ClpY, ClpQ/RcsA, and ClpQ/SulA. However, ClpY, lacking domain I (ClpY^I) was able to interact with itself and with intact ClpY. The C-terminal region of ClpY is important for interaction with other ClpY subunits. The previously defined PDZ-like domains at the C terminus of ClpY, including both D1 and D2, were determined to be indispensable for substrate binding. Various deletion and random point mutants of SulA were also made to verify significant interactions with ClpY. Thus, we demonstrated in vivo hetero- and homointeractions of ClpQ and ClpY molecules, as well as a direct association between ClpY and substrate SulA, thereby supporting previous in vitro biochemical findings.

---

* Corresponding author. Mailing address: Bldg. 2, R311, Department of Agricultural Chemistry, National Taiwan University, Taipei 106, Taiwan. Phone: (0118862) 2363-0231, x3395. Fax: (0118862) 2363-3123. E-mail: whifinwu{at}ccms.ntu.edu.tw.

---

Journal of Bacteriology, April 2003, p. 2393-2401, Vol. 185, No. 8
0021-9193/03/$08.00+0     DOI: 10.1128/JB.185.8.2393-2401.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Lien, H.-Y., Shy, R.-S., Peng, S.-S., Wu, Y.-L., Weng, Y.-T., Chen, H.-H., Su, P.-C., Ng, W.-F., Chen, Y.-C., Chang, P.-Y., Wu, W.-F. (2009). Characterization of the Escherichia coli ClpY (HslU) Substrate Recognition Site in the ClpYQ (HslUV) Protease Using the Yeast Two-Hybrid System. J. Bacteriol. 191: 4218-4231 [Abstract] [Full Text]  
• Kuo, M.-S., Chen, K.-P., Wu, W. F. (2004). Regulation of RcsA by the ClpYQ (HslUV) protease in Escherichia coli. Microbiology 150: 437-446 [Abstract] [Full Text]