title: Anionic lipid binding to the foreign protein MGS provides a tight coupling between phospholipid synthesis and protein overexpression in Escherichia coli.
abstract: Certain membrane proteins involved in lipid synthesis can induce formation of new intracellular membranes in Escherichia coli, i.e., intracellular vesicles. Among those, the foreign monotopic glycosyltransferase MGS from Acholeplasma laidlawii triggers such massive lipid synthesis when overexpressed. To examine the mechanism behind the increased lipid synthesis, we investigated the lipid binding properties of MGS in vivo together with the correlation between lipid synthesis and MGS overexpression levels. A good correlation between produced lipid quantities and overexpressed MGS protein was observed when standard LB medium was supplemented with four different lipid precursors that have significant roles in the lipid biosynthesis pathway. Interestingly, this correlation was highest concerning anionic lipid production and at the same time dependent on the selective binding of anionic lipid molecules by MGS. A selective interaction with anionic lipids was also observed in vitro by (31)P NMR binding studies using bicelles prepared with E. coli lipids. The results clearly demonstrate that the discriminative withdrawal of anionic lipids, especially phosphatidylglycerol, from the membrane through MGS binding triggers an in vivo signal for cells to create a "feed-forward" stimulation of lipid synthesis in E. coli. By this mechanism, cells can produce more membrane surface in order to accommodate excessively produced MGS molecules, which results in an interdependent cycle of lipid and MGS protein synthesis.
authors.affiliation: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden. candan@dbb.su.se
authors.forename: Candan
authors.initials: C
authors.lastname: Ariöz
authors.forename: Weihua
authors.initials: W
authors.lastname: Ye
authors.forename: Amin
authors.initials: A
authors.lastname: Bakali
authors.forename: Changrong
authors.initials: C
authors.lastname: Ge
authors.forename: Jobst
authors.initials: J
authors.lastname: Liebau
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Götzke
authors.forename: Andreas
authors.initials: A
authors.lastname: Barth
authors.forename: Ake
authors.initials: A
authors.lastname: Wieslander
authors.forename: Lena
authors.initials: L
authors.lastname: Mäler
mesh_terms: D000085:Acetates / Q000378:metabolism; D000128:Acholeplasma laidlawii / Q000201:enzymology* / Q000235:genetics; D000838:Anions / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001667:Binding, Competitive; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D015999:Multivariate Analysis; D009154:Mutation; D010743:Phospholipids / Q000096:biosynthesis* / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017550:Spectroscopy, Fourier Transform Infrared; D014170:Transformation, Genetic
chemical_list: D000085:Acetates; D000838:Anions; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010743:Phospholipids; D005964:Glucosyltransferases; C103660:1,2-diacylglycerol 3-glucosyltransferase