Differential effects of yfgL mutation on Escherichia coli outer membrane proteins and lipopolysaccharide.

نویسندگان

  • Emily S Charlson
  • John N Werner
  • Rajeev Misra
چکیده

YfgL together with NlpB, YfiO, and YaeT form a protein complex to facilitate the insertion of proteins into the outer membrane of Escherichia coli. Without YfgL, the levels of OmpA, OmpF, and LamB are significantly reduced, while OmpC levels are slightly reduced. In contrast, the level of TolC significantly increases in a yfgL mutant. When cells are depleted of YaeT or YfiO, levels of all outer membrane proteins examined, including OmpC and TolC, are severely reduced. Thus, while the assembly pathways of various nonlipoprotein outer membrane proteins may vary through the step involving YfgL, all assembly pathways in Escherichia coli converge at the step involving the YaeT/YfiO complex. The negative effect of yfgL mutation on outer membrane proteins may in part be due to elevated sigma E activity, which has been shown to downregulate the synthesis of various outer membrane proteins while upregulating the synthesis of periplasmic chaperones, foldases, and lipopolysaccharide. The data presented here suggest that the yfgL effect on outer membrane proteins also stems from a defective assembly apparatus, leading to aberrant outer membrane protein assembly, except for TolC, which assembles independent of YfgL. Consistent with this view, the simultaneous absence of YfgL and the major periplasmic protease DegP confers a synthetic lethal phenotype, presumably due to the toxic accumulation of unfolded outer membrane proteins. The results support the hypothesis that TolC and major outer membrane proteins compete for the YaeT/YfiO complex, since mutations that adversely affect synthesis or assembly of major outer membrane proteins lead to elevated TolC levels.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Strong decrease in invasive ability and outer membrane vesicle release in Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 with the yfgL gene deleted.

Adherent-invasive Escherichia coli strain LF82 recovered from a chronic lesion of a patient with Crohn's disease is able to invade cultured intestinal epithelial cells. Three mutants with impaired ability to invade epithelial cells had the Tn5phoA transposon inserted in the yfgL gene encoding the YfgL lipoprotein. A yfgL- negative isogenic mutant showed a marked decrease both in its ability to ...

متن کامل

SDS-PAGE Analysis of the Outer Membrane Proteins of Uropathogenic Escherichia coli Isolated from Patients in Different Wards of Nemazee Hospital, Shiraz, Iran

Background: Outer membrane proteins (OMPs) constitute the main structure and about half of the cell wall of Gram-negative bacteria. The OMPs of Escherichia coli (E. coli) play an important role in its drug resistance. Previous studies have shown that the OMPs of E. coli enhance its pathogenic effects by helping the bacterium to evade the immune defense and promote its adsorption to host cells. ...

متن کامل

Analysis of YfgL and YaeT interactions through bioinformatics, mutagenesis, and biochemistry.

In Escherichia coli, YaeT, together with four lipoproteins, YfgL, YfiO, NlpB, and SmpA, forms a complex that is essential for beta-barrel outer membrane protein biogenesis. Data suggest that YfgL and YfiO make direct but independent physical contacts with YaeT. Whereas the YaeT-YfiO interaction needs NlpB and SmpA for complex stabilization, the YaeT-YfgL interaction does not. Using bioinformati...

متن کامل

Chemical Conditionality A GeneticStrategy to Probe Organelle Assembly

The assembly of the Escherichia coli outer membrane (OM) is poorly understood. Although insight into fundamental cellular processes is often obtained from studying mutants, OM-defective mutants have not been very informative because they generally have nonspecific permeability defects. Here we show that toxic small molecules can be used in selections employing strains with permeability defects ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of bacteriology

دوره 188 20  شماره 

صفحات  -

تاریخ انتشار 2006