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Title: Protease homolog BepA (YfgC) promotes assembly and degradation of β-barrel membrane proteins in Escherichia coli
Authors: Narita, Shin-Ichiro
Masui, Chigusa
Suzuki, Takehiro
Dohmae, Naoshi
Akiyama, Yoshinori  kyouindb  KAKEN_id  orcid (unconfirmed)
Author's alias: 成田, 新一郎
舛井, 千草
鈴木, 健裕
堂前, 直
秋山, 芳展
Keywords: extracytoplasmic function sigma factor
protein quality control
disulfide bond formation
peptidase M48
tetratricopeptide repeat (TPR) motif
Issue Date: 3-Sep-2013
Publisher: National Academy of Sciences
Journal title: Proceedings of the National Academy of Sciences of the United States of America
Abstract: Gram-negative bacteria are equipped with quality-control systems for the outer membrane (OM) that sense and cope with defective biogenesis of its components. Accumulation of misfolded outer membrane proteins (OMPs) in Escherichia coli leads to activation of σ(E), an essential alternative σ factor that up-regulates transcription of multiple genes required to preserve OM structure and function. Disruption of bepA (formerly yfgC), a σ(E)-regulated gene encoding a putative periplasmic metalloprotease, sensitizes cells to multiple drugs, suggesting that it may be involved in maintaining OM integrity. However, the specific function of BepA remains unclear. Here, we show that BepA enhances biogenesis of LptD, an essential OMP involved in OM transport and assembly of lipopolysaccharide, by promoting rearrangement of intramolecular disulfide bonds of LptD. In addition, BepA possesses protease activity and is responsible for the degradation of incorrectly folded LptD. In the absence of periplasmic chaperone SurA, BepA also promotes degradation of BamA, the central OMP subunit of the β-barrel assembly machinery (BAM) complex. Interestingly, defective oxidative folding of LptD caused by bepA disruption was partially suppressed by expression of protease-active site mutants of BepA, suggesting that BepA functions independently of its protease activity. We also show that BepA has genetic and physical interaction with components of the BAM complex. These findings raised the possibility that BepA maintains the integrity of OM both by promoting assembly of OMPs and by proteolytically eliminating OMPs when their correct assembly was compromised.
Description: 膜タンパク質の組立と分解に関わる新規プロテアーゼを発見. 京都大学プレスリリース. 2013-09-03.
Rights: ©2013 by the National Academy of Sciences
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
DOI(Published Version): 10.1073/pnas.1312012110
PubMed ID: 24003122
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