The author uses classical thermal physics and physical chemistry to explain our current understanding of the membrane.
He looks at domain and 'raft' formation, and discusses it in the context of thermal fluctuations that express themselves in heat capacity and elastic constants. Further topics are lipid-protein interactions, protein binding, and the effect of sterols and anesthetics. Many seemingly unrelated properties of membranes are shown to be intimately intertwined, leading for instance to a coupling between membrane state, domain formation and vesicular shape.
In: Lyubchenko Y. Methods in Molecular Biology, vol Matin, K.
Molecular biophysics | Scientific Reports
Sigdel, M. Utjesanovic, B. Marsh, F. Gallazzi, V. Smith, I. Kosztin and G. Miller, A. Castaneda, K. Lee, M. Sanchez, A. Ortiz , E. Almaz , Z. Almaz , S. Murinda , W. Lin and E. Chada, K. Sigdel, R. Gari, T. Matin, L. Randall and G. Small, A. Yoo, T. Stahlheber, S.
Thermal Biophysics of Membranes (Tutorials in Biophysics)
Vandervoort, K. P Sigdel, J. Grayer, and G.
- Changing Substance Abuse and Criminal Behavior Through Therapeutic Relationships.
- Antares Victory;
- Mill (Arguments of the Philosophers).
Salik, M. Medrano, G. Cohoon, J. Coats Some proteins self-assemble into rigid, curved, shell-like structures forming coats, which, bound to the membrane, impose their curvature onto the bilayer.
Figure 3. Motor-driven formation of membrane tubules on microtubule tracks. Line Tension We have listed here a series of bending mechanisms involving proteins inserted into or bound onto membranes. Figure 4. BOX 3. Control of the Carrier Size Most proteins that deform membranes through the generation of spontaneous membrane curvature or by a crowding mechanism produce elongated membrane tubules and not spherical buds.
Scission A lipid membrane can be disrupted upon application of a high stretching force. Line Tension The scission of a bud or tubule requires overcoming an energy barrier in the process. Figure 5. Membrane Tension and Pulling Forces Interestingly, the increase of membrane tension that results from a reduced tubule radius considerably decreases the time for scission after phase separation Allain et al.
Scission Proteins Dynamin or dynamin-like proteins induce membrane scission by converting chemical energy of GTP into a squeezing force on the membrane neck Chappie et al. Helix Insertion Local destabilization of the membrane upon hydrophobic insertion is an alternative mechanism for fission. Experimental Systems As seen above, different mechanisms account for membrane bending and scission. From Apparently Simple to Complex: Construction of Endocytic Pits In going from simple to more evolved organisms, an apparent complexification of the endocytic machinery can be observed.
Inducing versus Sensing An important question that has caused some confusion is whether BAR-domain proteins are curvature sensors or inducers. From Apparently Simple to Complex: Membrane Scission Biological membrane scission is another example for which the from-simple-to-complex paradigm appears to apply. A Rafty Bending Business It is now clearly established that the plasma membrane is compartmentalized.
BOX 4. Previous Section. Membrane shape modulates trans -membrane protein distribution. Dev Cell to be published. Google Scholar. Fission of a multiphase membrane tube. Phys Rev Lett 93 : CrossRef Medline Google Scholar. Antonny B Antonny B. Mechanisms of membrane curvature sensing. Annu Rev Biochem 80 : — Sterol structure determines the separation of phases and the curvature of the liquid-ordered phase in model membranes. Proc Natl Acad Sci : — GTPase cycle of dynamin is coupled to membrane squeeze and release, leading to spontaneous fission. Cell : — Imaging coexisting fluid domains in biomembrane models coupling curvature and line tension.
Nature : — A unifying mechanism accounts for sensing of membrane curvature by BAR domains, amphipathic helices and membrane-anchored proteins. Sem Cell Dev Biol 21 : — Membrane fission is promoted by insertion of amphipathic helices and is restricted by crescent BAR domains.
Actin dynamics counteract membrane tension during clathrin-mediated endocytosis. Nat Cell Biol 13 : — Retromer: A master conductor of endosome sorting. Cold Spring Harb Perspect Biol doi: CrossRef Google Scholar. Membrane fission: The biogenesis of transport carriers. Ann Rev Biochem 81 : — The hydrophobic insertion mechanism of membrane curvature generation by proteins. Biophys J 95 : — Cholesterol-sensitive Cdc42 activation regulates actin polymerization for endocytosis via the GEEC pathway.
Traffic 8 : — A pseudoatomic model of the dynamin polymer identifies a hydrolysis-dependent powerstroke. Spatiotemporal regulation of chemical reactions by active cytoskeletal remodeling. The first five seconds in the life of a clathrin-coated pit.