Dynamics in the plasma membrane: how to combine fluidity and order

Abstract

Cell membranes are fascinating supramolecular aggregates that not only form a barrier between compartments but also harbor many chemical reactions essential to the existence and functioning of a cell. Here, it is proposed to review the molecular dynamics and mosaic organization of the plasma membrane, which are thought to have important functional implications. We will first summarize the basic concepts of Brownian diffusion and lipid domain formation in model membranes and then track the development of ideas and tools in this field, outlining key results obtained on the dynamic processes at work in membrane structure and assembly. We will focus in particular on findings made using fluorescent labeling and imaging procedures to record these dynamic processes. We will also discuss a few examples showing the impact of lateral diffusion on cell signal transduction, and outline some future methodological challenges which must be met before we can answer some of the questions arising in this field of research.

Progesterone facilitates cisplatin toxicity in epithelial ovarian cancer cells and xenografts

“…We suspect that the therapeutic gains on cells/tumors invoked by progesterone (both in the absence and presence of cisplatin) were related to a fluidity disorder of the plasmalemma. Indeed, physical state of biological membranes, the equilibrium between molten liquid crystal and solid gel, is a critical determinant of cellular behaviors [15]. The hydrophobic planar ring of progesterone immobilizes the core acyl side-chains of membrane phospholipids hindering rotational mobility [16].…”

Fluorescence fluctuations analysis in nanoapertures: physical concepts and biological applications

“…Nonetheless, one could argue that t 0 values arise from the extrapolation of the diVusion laws for non-optically accessible values, and that we can only speculate on what would experimentally happen in such circumstances, especially since microdomains are thought to be far much smaller (Edidin 2003;Kusumi et al 2005;Marguet et al 2006;Simons and Ikonen 1997).…”

“…The concept has been reWned with the identiWcation of both lipid-dependent and cytoskeleton-based organizations as the main compartmentalizing forces at work at the plasma membrane (Edidin 2003;Kusumi et al 2005;Marguet et al 2006;Simons and Ikonen 1997).…”

“…Among them, Xuorescence correlation spectroscopy (FCS) which can be performed at physiological temperature on living cells, has successfully contributed unraveling lateral membrane heterogeneities (Haustein and Schwille 2007;Marguet et al 2006). This is because FCS averages thousands of single-diVusion events at a very low level of probe concentration, a critical requirement in membrane organization studies.…”

Characterization of the motion of membrane proteins using high-speed atomic force microscopy

“…2a, blue); it rattles around a fixed position (Fig. 2b, blue), and the calculated mean square displacement (MSD) as a function of the lag time indicates corralled sub-diffusive behaviour 20 (Fig. 2c, blue).…”