Chapter 1. Biological membranes architecture and function
E. Sackmann
Technische Universität München,
James-Franck-Strasse, D-85748 Garching, Germany
1. Introduction
1.1. Why are biomembranes a playground for physicists?2. Molecular architecture of biomembranes
1.2. Biomembranes enable the modular design of cells
2.1. Cell plasma membrane as three layered composite system with associated macromolecular network3. Molecular composition of the lipid/protein bilayer
2.2. Erythrocyte birth and membrane structure
3.1. Universalities and pecularities of lipid composition4. Regulation of osmotic equilibrium: an ubiquitous task of membranes
3.2. Membranes of cellular organelles exhibit characteristic distributions (patterns) of lipids
3.3. The four major subclasses of membrane proteins
3.4. Bilayer asymmetry is an essential feature of the modular design of cells
4.1. Ion and molecular transport is controlled by only a few classes of pumps5. Membrane synthesis, differentiation and recycling
4.2. P-type ATPase is a prototype of a functional protein which is powered by ATP-cleavage and driven by a conformational change following phosphorylation
4.3. Energetics and reversibility of pumps
4.4. The regulation of Na+ /K+ -ATPase activity by steroids as a prototype of drug action
4.5. Differentiation is often controlled by type and number of membrane associated pumps
4.6. The concerted action of many pumps holds electrochemical equilibrium and may control cell shape
5.1. Lipids are synthesized in the ER, the Golgi and the Mitochondria6. Vectorial organisation of cells and material flow during metabolism and secretion
5.2. Membrane and secretory proteins are synthesized by the ER and modified in the Golgi: afirststepsorting
5.3. Nascent proteins must be processed in various ways before their translocation to target spaces and membranes
5.4. Part of newly synthesized lipid and protein molecules are distributed on a molecular basis
6.1. Synopsis7. On global shape instabilities of cells
6.2. Phenomenology of trafficking from the ER to the plasma membrane
6.3. On the generation of lysosomes and lysosomal enzymes
6.4. Receptor mediated endocytosis of metabolites via coated pits: an example of vesicle and receptor recycling
6.5. The role of molecular filters for the directed material exchange and sorting
7.1. Phagocytosis8. On the interplay between fast randomization and local phase separation in biomembranes
7.2. On the export of cellular organelles by budding and secretion
8.1. Diseases are often associated with changes in lipid compositionAbbreviations
8.2. Two-dimensionality of membranes is essential for diffusion controlled processes and enables manipulation of lateral protein mobility over orders of magnitude
8.3. Hormone signal transduction: a possible example of the interplay between rapid lateral randomization and local aggregation
References