QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Nakatogawa, H. Articles by Ito, K. Search for Related Content PubMed PubMed Citation Articles by Nakatogawa, H. Articles by Ito, K. Social Bookmarking                   What's this?

RESEARCH PAPER

SecM facilitates translocase function of SecA by localizing its biosynthesis

Institute for Virus Research and CREST, Japan Science and Technology Corporation, Kyoto University, Kyoto 606-8507, Japan

"Arrest sequence" of Escherichia coli SecM interacts with the ribosomal exit tunnel and arrests its own translation elongation, which is released by cotranslational export of the nascent SecM chain. This property of SecM is essential for the basal and regulated expression of SecA. Here we report that SecM has an additional role of facilitating SecA activities. Systematic determinations of the SecA-abundance-protein export relationships of cells with different SecA contents revealed that SecA was less functional when SecM was absent from the upstream region of the secM–secA message, when SecM had the arrest-defective mutation, and also when SecM lacked the signal sequence. These results suggest that cotranslational targeting of nascent SecM to the translocon plays previously unrecognized roles of facilitating the formation of functional SecA molecules. Biosynthesis in the vicinity of the membrane and the Sec translocon will be beneficial for this multiconformation ATPase to adopt ready-to-function conformations.

[Keywords: SecM; SecA; Escherichia coli; protein secretion; cotranslational targeting; ribosomal tunnel]

Received September 8, 2004; revised version accepted December 15, 2004.

¹ Present address: Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan

² Corresponding author.

E-MAIL kito{at}virus.kyoto-u.ac.jp; FAX 81-75-771-5699.

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

This article has been cited by other articles:

				H. Mori and K. Ito The Long {alpha}-Helix of SecA Is Important for the ATPase Coupling of Translocation J. Biol. Chem., November 24, 2006; 281(47): 36249 - 36256. [Abstract] [Full Text] [PDF]

				F. Garza-Sanchez, B. D. Janssen, and C. S. Hayes Prolyl-tRNAPro in the A-site of SecM-arrested Ribosomes Inhibits the Recruitment of Transfer-messenger RNA J. Biol. Chem., November 10, 2006; 281(45): 34258 - 34268. [Abstract] [Full Text] [PDF]