Role of lipids in the translocation of proteins across membranes

2000 ◽  
Vol 347 (3) ◽  
pp. 601-612 ◽  
Author(s):  
Frank VAN VOORST ◽  
Ben DE KRUIJFF
Keyword(s):  
Endoplasmic Reticulum ◽  
Biochemical Characterization ◽  
Protein Translocation ◽  
Intimate Relationship ◽  
Membrane Lipid ◽  
Membrane Lipid Composition ◽  
Sorting Signals ◽  
Membrane Bound ◽  
Protein Components

The architecture of cells, with various membrane-bound compartments and with the protein synthesizing machinery confined to one location, dictates that many proteins have to be transported through one or more membranes during their biogenesis. A lot of progress has been made on the identification of protein translocation machineries and their sorting signals in various organelles and organisms. Biochemical characterization has revealed the functions of several individual protein components. Interestingly, lipid components were also found to be essential for the correct functioning of these translocases. This led to the idea that there is a very intimate relationship between the lipid and protein components that enables them to fulfil their intriguing task of transporting large biopolymers through a lipid bilayer without leaking their contents. In this review we focus on the Sec translocases in the endoplasmic reticulum and the bacterial inner membrane. We also highlight the interactions of lipids and proteins during the process of translocation and integrate this into a model that enables us to understand the role of membrane lipid composition in translocase function.

Dietary Selenium or Zinc Supplementation Restores Brain Lipid Composition and Membrane Fluidity in Protein-Undernourished Rats

2016 ◽  
Vol 38 (6) ◽  
pp. 397-406
Author(s):  
Olusegun L. Adebayo ◽  
Bamidele A. Salau ◽  
Rajat Sandhir ◽  
Gbenga A. Adenuga
Keyword(s):  
Membrane Fluidity ◽  
Lipid Composition ◽  
Zinc Supplementation ◽  
Protective Role ◽  
Membrane Lipid ◽  
Limited Information ◽  
Total Lipids ◽  
Major Focus ◽  
Membrane Lipid Composition

Studies have shown that protein undernutrition (PU) modifies the membrane lipid composition in the intestine and liver, as well as in plasma and other areas. However, there is limited information on the effect of PU on synaptosomal membrane lipid composition and fluidity and the protective role of selenium (Se) and zinc (Zn), which is a major focus of the present study. For 10 weeks, rats were fed diets containing 16% casein, which constituted the adequate protein diet, or 5% casein, representing the PU diet. The animals were supplemented with Se and Zn at a concentration of 0.15 and 227 mg L-1, respectively, in drinking water for 3 weeks. The results showed a significant increase in total lipids, glycolipids, triglycerides, cholesterol, and the cholesterol/phospholipid (Chol/PL) ratio, and a significant reduction in phospholipids and membrane fluidity. Se and Zn supplementation to PU rats, however, significantly lowered total lipids, glycolipids, triglycerides, cholesterol, and the Chol/PL ratio, while phospholipids and membrane fluidity were significantly restored. It is concluded that a perturbed lipid composition induced by PU affects the membrane structure and fluidity, which in turn influences membrane functions. The study suggests that Se and Zn supplementation might be beneficial in restoring the lipid dyshomeostasis associated with PU.

scholarly journals Occurrence of cross-resistance and β-lactam seesaw effect in glycopeptide-, lipopeptide- and lipoglycopeptide-resistant MRSA correlates with membrane phosphatidylglycerol levels

2020 ◽  
Vol 75 (5) ◽  
pp. 1182-1186 ◽  
Author(s):  
Kelly M Hines ◽  
Tianwei Shen ◽  
Nathaniel K Ashford ◽  
Adam Waalkes ◽  
Kelsi Penewit ◽  
...  
Keyword(s):  
Cell Wall ◽  
Susceptibility Testing ◽  
Membrane Lipid ◽  
Cross Resistance ◽  
Membrane Composition ◽  
Membrane Lipid Composition ◽  
Usa300 Strain ◽  
Associated Proteins ◽  
The Relationship

Abstract Background Glycopeptides (GPs), lipopeptides (LPs) and lipoglycopeptides (LGPs) are related antimicrobials important for the management of invasive MRSA infections. Cross-resistance among these antibiotics in MRSA is well documented, as is the observation that susceptibility of MRSA to β-lactams increases as susceptibility to GPs and LPs decreases (i.e. the seesaw effect). Efforts to understand the relationship between GP/LP/LGP cross-resistance and the seesaw effect have focused on the PBPs, but the role of lipid metabolism has not been investigated. Objectives Since the cell membrane is structurally and metabolically integrated with the cell wall and anchors associated proteins, including PBPs, we examined the relationship between membrane lipid composition and the phenomena of cross-resistance among GPs/LPs/LGPs and the β-lactam seesaw effect. Methods We selected for daptomycin, vancomycin and dalbavancin resistance using the USA300 strain JE2 and evaluated the resulting mutants by WGS, MS-based lipidomics and antimicrobial susceptibility testing to assess the relationship between membrane composition, cross-resistance, and the seesaw effect. Results We observed cross-resistance to GPs/LPs/LGPs among the selected strains and the seesaw effect against various β-lactams, depending on the PBP targets of the particular β-lactam. We found that modification of membrane composition occurs not only in daptomycin-selected strains, but also vancomycin- and dalbavancin-selected strains. Significantly, we observed that the abundance of most phosphatidylglycerols positively correlates with MICs of GPs/LPs/LGPs and negatively correlates with the MICs of β-lactams. Conclusions These studies demonstrate a major association between membrane remodelling, cross-resistance and the seesaw effect.

scholarly journals Role of Protein Translocation Pathways across the Endoplasmic Reticulum inTrypanosoma brucei

2008 ◽  
Vol 283 (46) ◽  
pp. 32085-32098 ◽  
Author(s):  
Hanoch Goldshmidt ◽  
Lilach Sheiner ◽  
Peter Bütikofer ◽  
Isabel Roditi ◽  
Shai Uliel ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Translocation

scholarly journals P4-199: Role of γ secretase in the cellular membrane lipid composition

2008 ◽  
Vol 4 ◽  
pp. T729-T730
Author(s):  
Jessica Hommes ◽  
Jochen Walter ◽  
Bernadette Breiden ◽  
Irfan Y. Tamboli ◽  
Günter Schwarzmann
Keyword(s):  
Lipid Composition ◽  
Cellular Membrane ◽  
Membrane Lipid ◽  
Membrane Lipid Composition

Biochemistry and site-directed mutational analysis of Δ7-sterol-C5(6)-desaturase

2000 ◽  
Vol 28 (6) ◽  
pp. 799-803 ◽  
Author(s):  
A. Rahier ◽  
P. Benveniste ◽  
T. Husselstein ◽  
M. Taton
Keyword(s):  
Biochemical Characterization ◽  
Mutational Analysis ◽  
Enzyme System ◽  
Conserved Residues ◽  
Catalytic Role ◽  
Membrane Bound ◽  
Haem Iron ◽  
Oxygen Site

This report describes recent work on the process of desaturation at C5(6) of sterol precursors in plants. Biochemical characterization of the plant Δ7-sterol C5(6)-desaturase (5-DES) indicates that the enzyme system involved shows important similarities to the soluble and membrane-bound non-haem iron desaturases found in eukaryotes, including cyanide and hydrophobic chelators sensitivity, CO resistance and a requirement for exogenous reductant and molecular oxygen. Site-directed mutational analysis of highly conserved residues in 5-DES indicated that eight histidine residues from three histidine-rich motifs were essential for the catalysis, possibly by providing the ligands for a putative Fe centre. This mutational analysis also revealed the catalytic role of the functionally conserved Thr-114.

Sign in / Sign up

Export Citation Format

Share Document