title: Exploring the binding dynamics of BAR proteins.
abstract: We used a continuum model based on the Helfrich free energy to investigate the binding dynamics of a lipid bilayer to a BAR domain surface of a crescent-like shape of positive (e.g. I-BAR shape) or negative (e.g. F-BAR shape) intrinsic curvature. According to structural data, it has been suggested that negatively charged membrane lipids are bound to positively charged amino acids at the binding interface of BAR proteins, contributing a negative binding energy to the system free energy. In addition, the cone-like shape of negatively charged lipids on the inner side of a cell membrane might contribute a positive intrinsic curvature, facilitating the initial bending towards the crescent-like shape of the BAR domain. In the present study, we hypothesize that in the limit of a rigid BAR domain shape, the negative binding energy and the coupling between the intrinsic curvature of negatively charged lipids and the membrane curvature drive the bending of the membrane. To estimate the binding energy, the electric potential at the charged surface of a BAR domain was calculated using the Langevin-Bikerman equation. Results of numerical simulations reveal that the binding energy is important for the initial instability (i.e. bending of a membrane), while the coupling between the intrinsic shapes of lipids and membrane curvature could be crucial for the curvature-dependent aggregation of negatively charged lipids near the surface of the BAR domain. In the discussion, we suggest novel experiments using patch clamp techniques to analyze the binding dynamics of BAR proteins, as well as the possible role of BAR proteins in the fusion pore stability of exovesicles.
authors: Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia. doron.kabaso@fe.uni-lj.si
authors: Doron
authors: D
authors: Kabaso
authors: Ekaterina
authors: E
authors: Gongadze
authors: Jernej
authors: J
authors: Jorgačevski
authors: Marko
authors: M
authors: Kreft
authors: Ursula
authors: U
authors: Van Rienen
authors: Robert
authors: R
authors: Zorec
authors: Aleš
authors: A
authors: Iglič
references: Comput Methods Biomech Biomed Engin. 2011 May;14(5):469-82
references: 21516531
references: Phys Rev Lett. 1994 Aug 22;73(8):1186-1189
references: 10057646
references: Cell. 2009 Apr 17;137(2):191-6
references: 19379681
references: Biophys J. 2007 Dec 1;93(11):3798-810
references: 17704150
references: Nature. 2001 May 10;411(6834):215-9
references: 11346801
references: Gen Physiol Biophys. 2011 Jun;30(2):130-7
references: 21613667
references: Nat Rev Mol Cell Biol. 2006 Jan;7(1):9-19
references: 16365634
references: Mol Membr Biol. 2010 Apr;27(2-3):65-80
references: 20334578
references: Proc Natl Acad Sci U S A. 2009 Aug 4;106(31):12700-5
references: 19549836
references: FEBS Lett. 1990 Oct 29;273(1-2):150-4
references: 2172025
references: Curr Biol. 2004 Mar 23;14(6):R250-2
references: 15043839
references: Mini Rev Med Chem. 2011 Apr;11(4):272-82
references: 21428902
references: J Cell Sci. 2008 Jun 15;121(Pt 12):1951-4
references: 18525024
references: Neuron. 2009 Jun 11;62(5):683-94
references: 19524527
references: Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Apr;73(4 Pt 1):041915
references: 16711844
references: Biochim Biophys Acta. 2006 Aug;1761(8):897-912
references: 16938488
references: Chem Phys Lipids. 2009 Jan;157(1):12-20
references: 18938147
references: Science. 2004 Jan 23;303(5657):495-9
references: 14645856
references: FEBS Lett. 1992 Jun 1;303(2-3):221-3
references: 1607022
references: Bioelectrochemistry. 2010 Oct;79(2):223-7
references: 20678740
references: Z Naturforsch C. 1973 Nov-Dec;28(11):693-703
references: 4273690
references: Proc Natl Acad Sci U S A. 1982 Nov;79(21):6712-6
references: 6959149
references: J Biomech. 2007;40(11):2492-500
references: 17198707
references: Biophys J. 2009 Sep 16;97(6):1626-35
references: 19751667
references: Pflugers Arch. 1981 Aug;391(2):85-100
references: 6270629
references: FEBS Lett. 2010 Mar 19;584(6):1111-8
references: 20188097
references: Biophys J. 2010 Aug 4;99(3):808-16
references: 20682258
references: Pflugers Arch. 1997 Jun;434(2):212-4
references: 9136678
references: J Cell Biol. 2001 Oct 15;155(2):193-200
references: 11604418
references: Proc Natl Acad Sci U S A. 2006 Oct 10;103(41):15068-72
references: 17008407
references: Int J Nanomedicine. 2011;6:495-509
references: 21468353