A mutant form of SecY, SecY1, was previously suggested to sequester a component(s) of the protein translocator complex. Its synthesis from a plasmid leads to interference with protein export in Escherichia coli. SecE is a target of this sequestration, and its overproduction cancels the export interference. We now report that overexpression of another gene, termed syd, also suppresses secY1. The nucleotide sequence of syd predicted that it encodes a protein of 181 amino acid residues, which has been identified by overproduction, purification, and determination of the amino-terminal sequence. Cell fractionation experiments suggested that Syd is loosely associated with the cytoplasmic surface of the cytoplasmic membrane. SecY may be involved in the membrane association of Syd since the association is saturable, the extent of which depends on the overproduction of SecY. SecY is rapidly degraded in vivo unless its primary partner, SecE, is sufficiently available. Overproduction of Syd was found to stabilize oversynthesized SecY. However, Syd cannot stabilize the SecY1 form of SecY. Thus, in the presence of both secY and secY1, Syd increases the effective SecY/SecY1 ratio in the cell and cancels the dominant interference by the latter. We also found that overproduction of Syd dramatically inhibits protein export in the secY24 mutant cell in which SecY-SecE interaction has been weakened. These results indicate that Syd, especially when it is overproduced, has abilities to interact with SecY. Possible significance of such interactions is discussed in conjunction with the apparent lack of phenotypic consequences of genetic disruption of syd.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				N. Shimohata, S. Nagamori, Y. Akiyama, H. R. Kaback, and K. Ito SecY alterations that impair membrane protein folding and generate a membrane stress J. Cell Biol., January 29, 2007; 176(3): 307 - 317. [Abstract] [Full Text] [PDF]

				M. Sakoh, K. Ito, and Y. Akiyama Proteolytic Activity of HtpX, a Membrane-bound and Stress-controlled Protease from Escherichia coli J. Biol. Chem., September 30, 2005; 280(39): 33305 - 33310. [Abstract] [Full Text] [PDF]

				N. Shimohata, Y. Akiyama, and K. Ito Peculiar Properties of DsbA in Its Export across the Escherichia coli Cytoplasmic Membrane J. Bacteriol., June 15, 2005; 187(12): 3997 - 4004. [Abstract] [Full Text] [PDF]

				H. Nakatogawa, A. Murakami, H. Mori, and K. Ito SecM facilitates translocase function of SecA by localizing its biosynthesis Genes & Dev., February 15, 2005; 19(4): 436 - 444. [Abstract] [Full Text] [PDF]

				A. Murakami, H. Nakatogawa, and K. Ito Translation arrest of SecM is essential for the basal and regulated expression of SecA PNAS, August 17, 2004; 101(33): 12330 - 12335. [Abstract] [Full Text] [PDF]

				S. Nagamori, I. N. Smirnova, and H. R. Kaback Role of YidC in folding of polytopic membrane proteins J. Cell Biol., April 12, 2004; 165(1): 53 - 62. [Abstract] [Full Text] [PDF]

				H. Mori, Y. Akiyama, and K. Ito A SecE Mutation That Modulates SecY-SecE Translocase Assembly, Identified as a Specific Suppressor of SecY Defects J. Bacteriol., February 1, 2003; 185(3): 948 - 956. [Abstract] [Full Text] [PDF]

				H. Mori, Y. Shimizu, and K. Ito Superactive SecY Variants That Fulfill the Essential Translocation Function with a Reduced Cellular Quantity J. Biol. Chem., December 6, 2002; 277(50): 48550 - 48557. [Abstract] [Full Text] [PDF]

				K. Kanehara, K. Ito, and Y. Akiyama YaeL (EcfE) activates the sigma E pathway of stress response through a site-2 cleavage of anti-sigma E, RseA Genes & Dev., August 15, 2002; 16(16): 2147 - 2155. [Abstract] [Full Text] [PDF]

				K. Chiba, H. Mori, and K. Ito Roles of the C-Terminal End of SecY in Protein Translocation and Viability of Escherichia coli J. Bacteriol., April 15, 2002; 184(8): 2243 - 2250. [Abstract] [Full Text]

				M. K. B. Berlyn Linkage Map of Escherichia coli K-12, Edition 10: The Traditional Map Microbiol. Mol. Biol. Rev., September 1, 1998; 62(3): 814 - 984. [Abstract] [Full Text] [PDF]

				Y. Akiyama, A. Kihara, H. Mori, T. Ogura, and K. Ito Roles of the Periplasmic Domain of Escherichia coli FtsH (HflB) in Protein Interactions and Activity Modulation J. Biol. Chem., August 28, 1998; 273(35): 22326 - 22333. [Abstract] [Full Text] [PDF]

				E.-i. Matsuo, H. Mori, T. Shimoike, and K. Ito Syd, a SecY-interacting Protein, Excludes SecA from the SecYE Complex with an Altered SecY24 Subunit J. Biol. Chem., July 24, 1998; 273(30): 18835 - 18840. [Abstract] [Full Text] [PDF]

				K. Sato, H. Mori, M. Yoshida, M. Tagaya, and S. Mizushima In Vitro Analysis of the Stop-transfer Process during Translocation across the Cytoplasmic Membrane of Escherichia coli J. Biol. Chem., August 8, 1997; 272(32): 20082 - 20087. [Abstract] [Full Text] [PDF]

				M. Y. Liu, G. Gui, B. Wei, J. F. Preston III, L. Oakford, U. Yuksel, D. P. Giedroc, and T. Romeo The RNA Molecule CsrB Binds to the Global Regulatory Protein CsrA and Antagonizes Its Activity in Escherichia coli J. Biol. Chem., July 11, 1997; 272(28): 17502 - 17510. [Abstract] [Full Text] [PDF]

				Y.-B. Yang, N. Yu, and P. C. Tai SecE-depleted Membranes of Escherichia coli Are Active. SecE IS NOT OBLIGATORILY REQUIRED FOR THE IN VITRO TRANSLOCATION OF CERTAIN PROTEIN PRECURSORS J. Biol. Chem., May 23, 1997; 272(21): 13660 - 13665. [Abstract] [Full Text] [PDF]

				M. Sone, Y. Akiyama, and K. Ito Differential in Vivo Roles Played by DsbA and DsbC in the Formation of Protein Disulfide Bonds J. Biol. Chem., April 18, 1997; 272(16): 10349 - 10352. [Abstract] [Full Text] [PDF]

				M. Sone, S. Kishigami, T. Yoshihisa, and K. Ito Roles of Disulfide Bonds in Bacterial Alkaline Phosphatase J. Biol. Chem., March 7, 1997; 272(10): 6174 - 6178. [Abstract] [Full Text] [PDF]

				Y. Akiyama, A. Kihara, H. Tokuda, and K. Ito FtsH (HflB) Is an ATP-dependent Protease Selectively Acting on SecY and Some Other Membrane Proteins J. Biol. Chem., December 6, 1996; 271(49): 31196 - 31201. [Abstract] [Full Text] [PDF]

				T. Yoshihisa and K. Ito Pro-OmpA Derivatives with a His(6) Tag in Their N-terminal ``Translocation Initiation Domains'' Are Arrested by Ni[IMAGE] at an Early Post-targeting Stage of Translocation J. Biol. Chem., April 19, 1996; 271(16): 9429 - 9436. [Abstract] [Full Text] [PDF]