This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.107.118380v1 94/8/2938    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Alley, S. H. Articles by Barahona, M. PubMed PubMed Citation Articles by Alley, S. H. Articles by Barahona, M.

Biophysical Regulation of Lipid Biosynthesis in the Plasma Membrane

Stephen H. Alley ^*, Oscar Ces , Richard H. Templer  and Mauricio Barahona ^* 

^* Department of Bioengineering, Department of Chemistry and Institute for Mathematical Sciences, Imperial College London, South Kensington Campus, London, United Kingdom

Correspondence: Address reprint requests to M. Barahona, E-mail: m.barahona{at}imperial.ac.uk.

We present a cellular model of lipid biosynthesis in the plasma membrane that couples biochemical and biophysical features of the enzymatic network of the cell-wall-less Mycoplasma Acholeplasma laidlawii. In particular, we formulate how the stored elastic energy of the lipid bilayer can modify the activity of curvature-sensitive enzymes through the binding of amphipathic -helices. As the binding depends on lipid composition, this results in a biophysical feedback mechanism for the regulation of the stored elastic energy. The model shows that the presence of feedback increases the robustness of the steady state of the system, in the sense that biologically inviable nonbilayer states are less likely. We also show that the biophysical and biochemical features of the network have implications as to which enzymes are most efficient at implementing the regulation. The network imposes restrictions on the steady-state balance between bilayer and nonbilayer lipids and on the concentrations of particular lipids. Finally, we consider the influence of the length of the amphipathic -helix on the efficacy of the feedback and propose experimental measurements and extensions of the modeling framework.