Enzymology, genetics, and regulation of membrane phospholipid synthesis in Escherichia coli.

Raetz, Christian R. H.

doi:10.1128/mmbr.42.3.614-659.1978

Cited by 228 publications

(148 citation statements)

References 238 publications

(592 reference statements)

Supporting

Mentioning

141

Contrasting

Order By: Relevance

“…Introduction of [14C]DOPE in cation depleted AD93 vesicles could be achieved by incubation (PS). This is a very rapid process which is catalyzed by the cytosolic enzyme PS-decarboxylase (Raetz, 1978), which is tightly membrane associated. In the inside-out membrane vesicles this enzyme is exposed on the outside.…”

Section: Ad93 Inverted Membrane Vesicles Can Generate Amentioning

confidence: 99%

Non-bilayer lipids are required for efficient protein transport across the plasma membrane of Escherichia coli.

1995

View full text Add to dashboard Cite

The construction of a mutant Escherichia coli strain which cannot synthesize phosphatidylethanolamine provides a tool to study the involvement of non‐bilayer lipids in membrane function. This strain produces phosphatidylglycerol and cardiolipin (CL) as major membrane constituents and requires millimolar concentrations of divalent cations for growth. In this strain, the lipid phase behaviour is tightly regulated by adjustment of the level of CL which favours a nonbilayer organization in the presence of specific divalent cations. We have used an in vitro system of inverted membrane vesicles to study the involvement of non‐bilayer lipids in protein translocation in the secretion pathway. In this system, protein translocation is very low in the absence of divalent cations but can be enhanced by inclusion of Mg2+, Ca2+ or Sr2+ but not by Ba2+ which is unable to sustain growth of the mutant strain and cannot induce a non‐bilayer phase in E. coli CL dispersions. Alternatively, translocation in cation depleted vesicles could be increased by incorporation of the non‐bilayer lipid DOPE (18:1) but not by DMPE (14:0) or DOPC (18:1), both of which are bilayer lipids under physiological conditions. We conclude that non‐bilayer lipids are essential for efficient protein transport across the plasma membrane of E. coli.

show abstract

Section: Ad93 Inverted Membrane Vesicles Can Generate Amentioning

confidence: 99%

Non-bilayer lipids are required for efficient protein transport across the plasma membrane of Escherichia coli.

1995

View full text Add to dashboard Cite

show abstract

“…Biological membranes contain a diversity of lipids which differ in the nature of their headgroups. The composition of the inner membrane of Escherichia coli is relatively simple, containing ∼75% of the zwitterionic lipid phosphatidylethanolamine (PE), 20% phosphatidylglycerol (PG) and 5% cardiolipin (CL); the latter two lipids are both negatively charged (Raetz, 1978). Because of this simplicity and the possibility of modulating the lipid composition of this organism, much is known about the functions of these lipids in E. coli, for example in membrane protein translocation.…”

Section: Introductionmentioning

confidence: 99%

Anionic lipids stimulate Sec‐independent insertion of a membrane protein lacking charged amino acid side chains

et al. 2001

View full text Add to dashboard Cite

We have investigated the influence of the different lipid classes of Escherichia coli on Sec-independent membrane protein insertion, using an assay in which a mutant of the single-spanning Pf3 coat protein is biosynthetically inserted into liposomes. It was found that phosphatidylethanolamine and other non-bilayer lipids do not have a significant effect on insertion. Surprisingly, the anionic lipids phosphatidylglycerol and cardiolipin stimulate N-terminal translocation of the protein, even though it has no charged amino acid side chains. This novel effect is general for anionic lipids and depends on the amount of charge on the lipid headgroup. Since the N-terminus of the protein is at least partially positively charged due to a helix dipole moment, apparently negatively charged lipids can stimulate translocation of slightly positively charged protein segments in a direction opposite to the positive-inside rule. A mechanism is proposed to explain these results.

show abstract

“…(e) Under all the conditions studied, the percentage of anionic phospholipid at the external surface of the plasma membrane calculated from the a values was 2.3-3.0 times less than that in the cells, indicating that the asymmetric composition (more inside) was maintained. A model for the regulation of the anionic phospholipid composition of the yeast membranes is proposed.The genetics and biochemistry of phospholipid biosynthesis have been extensively studied in Escherichia coli [1] and in the yeast Saccharomyces cerevisiae [2]. Many of the enzymes of phospholipid biosynthesis are known to be activated by lipids and/or detergents and, in general, anionic lipids are better activators than neutral lipids [3].…”

mentioning

confidence: 99%

Surface potential regulation of phospholipid composition and in‐out translocation in yeast

Cerbón¹,

Calderón²

1994

European Journal of Biochemistry

View full text Add to dashboard Cite

In yeast cells the anionic phospholipids, phosphatidylinositol and phosphatidylserine, determine to a large extent the magnitude of the negative surface charge density (a) [Cerbon, J. & Calderon, V, (1990) Biochim. Biophys. Acta 1028, 261-2671. We now report further findings. (a) When the yeast qoUt was reduced by increasing the concentration of monovalent (C') or divalent (C"+) cations in the culture medium, the relative amount of anionic phospholipids increased (45-52%). (b) For each such increment, a corresponding increase in the external surface charge density (a) was found, due to the translocation from the cytoplasmic side to the exoplasmic side of the plasma membrane. (c) These changes were reversed when the yl""' was increased by reducing the concentration of cations in the culture medium. (d) When the yo"' was reduced and phosphatidylserine decarboxylation or phosphatidylinositol degradation were inhibited, to measure synthesis of anionic phospholipids, a 1.4 times further increase in the anionic/zwitterionic phospholipid ratio occurred. As a consequence, a similar increase in the external surface charge (0) was found. (e) Under all the conditions studied, the percentage of anionic phospholipid at the external surface of the plasma membrane calculated from the a values was 2.3-3.0 times less than that in the cells, indicating that the asymmetric composition (more inside) was maintained. A model for the regulation of the anionic phospholipid composition of the yeast membranes is proposed.The genetics and biochemistry of phospholipid biosynthesis have been extensively studied in Escherichia coli [1] and in the yeast Saccharomyces cerevisiae [2]. Many of the enzymes of phospholipid biosynthesis are known to be activated by lipids and/or detergents and, in general, anionic lipids are better activators than neutral lipids [3]. The lipid dependence of these enzymes is of considerable interest, not only in the context of the general implications for lipidprotein interactions, but in view of the dual role of lipid molecules as subswate/products and modulators of activity. We have shown that anionic-phospholipid-rich cells have an increased surface potential (9""') which activates the highaffinity H-linked transport systems and inhibits the transport of anions from high external concentrations [4]. The activity of these membrane proteins ( K , and optimum pH) was regulated by the anionic phospholipids through their effects upon membrane electrostatics. Also, these changes in the membrane phospholipid composition modify their asymmetric distribution [5]. Taking into account that most phospholipid biosynthetic enzymes are membrane proteins, and that membrane phospholipid composition is one of the observed regulatory mechanisms in vitro [2], the effect of varying the external surface potential (@'"') upon the phospholipid composition and distribution in normal PtdIns-rich and PtdSer-rich cells was studied. The cell's pot'' was increased or decreased by altering the concentration of monovalent (NaC1) or divalent (M...

show abstract

Enzymology, genetics, and regulation of membrane phospholipid synthesis in Escherichia coli.

Cited by 228 publications

References 238 publications

Non-bilayer lipids are required for efficient protein transport across the plasma membrane of Escherichia coli.

Non-bilayer lipids are required for efficient protein transport across the plasma membrane of Escherichia coli.

Anionic lipids stimulate Sec‐independent insertion of a membrane protein lacking charged amino acid side chains

Surface potential regulation of phospholipid composition and in‐out translocation in yeast

Contact Info

Product

Resources

About