HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 281, Issue 41, 30347-30355, October 13, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/41/30347    most recent M601064200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Barker, M. Articles by Nixon, P. J. Search for Related Content PubMed PubMed Citation Articles by Barker, M. Articles by Nixon, P. J. Social Bookmarking                      What's this?

The Deg Proteases Protect Synechocystis sp. PCC 6803 during Heat and Light Stresses but Are Not Essential for Removal of Damaged D1 Protein during the Photosystem Two Repair Cycle^*

Myles Barker¹, Remco de Vries, Jon Nield², Josef Komenda^¶3, and Peter J. Nixon⁴

From the Divisions of Biology and Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom and the ^¶Institute of Microbiology, Academy of Sciences, Opatovickmln, 37981 Tebo, Czech Republic

Members of the DegP/HtrA (or Deg) family of proteases are found widely in nature and play an important role in the proteolysis of misfolded and damaged proteins. As yet, their physiological role in oxygenic photosynthetic organisms is unclear, although it has been widely speculated that they participate in the degradation of the photodamaged D1 subunit in the photosystem two complex (PSII) repair cycle, which is needed to maintain PSII activity in both cyanobacteria and chloroplasts. We have examined the role of the three Deg proteases found in the cyanobacterium Synechocystis sp. PCC 6803 through analysis of double and triple insertion mutants. We have discovered that these proteases show overlap in function and are involved in a number of key physiological responses ranging from protection against light and heat stresses to phototaxis. In previous work, we concluded that the Deg proteases played either a direct or an indirect role in PSII repair in a glucose-tolerant version of Synechocystis 6803 (Silva, P., Choi, Y. J., Hassan, H. A., and Nixon, P. J. (2002) Philos. Trans. R. Soc. Lond. B Biol. Sci. 357, 1461–1467). In this work, we have now been able to demonstrate unambiguously, using a triple deg mutant created in the wild type strain of Synechocystis 6803, that the Deg proteases are not obligatory for PSII repair and D1 degradation. We therefore conclude that although the Deg proteases are needed for photoprotection of Synechocystis sp. PCC 6803, they do not play an essential role in D1 turnover and PSII repair in vivo.

Received for publication, February 3, 2006 , and in revised form, July 24, 2006.

^* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ A recipient of a BBSRC ear-marked PhD studentship.

² Currently holds a Royal Society University Research Fellowship.

³ Supported by Institutional Research Concept AV0Z50200510.

⁴ To whom correspondence should be addressed: Division of Biology, Faculty of Natural Sciences, Imperial College London, S. Kensington campus, Wolfson Biochemistry Bldg., London SW7 2AZ, UK. Tel.: 44-20-7594-5269; Fax: 44-20-7594-5267; E-mail: p.nixon{at}imperial.ac.uk.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				P. F. Huesgen, P. Scholz, and I. Adamska The Serine Protease HhoA from Synechocystis sp. Strain PCC 6803: Substrate Specificity and Formation of a Hexameric Complex Are Regulated by the PDZ Domain J. Bacteriol., September 15, 2007; 189(18): 6611 - 6618. [Abstract] [Full Text] [PDF]

				J. Komenda, M. Tichy, O. Prasil, J. Knoppova, S. Kuvikova, R. de Vries, and P. J. Nixon The Exposed N-Terminal Tail of the D1 Subunit Is Required for Rapid D1 Degradation during Photosystem II Repair in Synechocystis sp PCC 6803 PLANT CELL, September 1, 2007; 19(9): 2839 - 2854. [Abstract] [Full Text] [PDF]

				X. Sun, L. Peng, J. Guo, W. Chi, J. Ma, C. Lu, and L. Zhang Formation of DEG5 and DEG8 Complexes and Their Involvement in the Degradation of Photodamaged Photosystem II Reaction Center D1 Protein in Arabidopsis PLANT CELL, April 1, 2007; 19(4): 1347 - 1361. [Abstract] [Full Text] [PDF]