Optical techniques for imaging membrane lipid microdomains in living cells.
Lateral organisation of cellular membranes, particularly the plasma membrane, is of benefit to the cell as it allows complicated cellular processes to be regulated and efficient. For example, trafficking and secretion of molecules can be targeted and directed, cells polarised and signalling events modulated and propagated. The fluid mosaic model allows for significant heterogeneity on the part of the lipids themselves and of membrane associated proteins. By exploiting the tendency of complex lipid bilayers to undergo spontaneous or induced phase-separation into non-miscible domains, the cell could achieve this desired spatial organisation. While phase-separation is readily observed in simple, artificial bilayers, its occurrence in physiological membranes remains controversial. This stems mainly from our inability to image lipid microdomains directly - possibly due to their small size, short lifespan and/or morphological similarity to the bulk membrane. In this review, we seek to examine the techniques used to try to image membrane lipid microdomains, concentrating mainly on optical microscopy techniques that are applicable to live cells. We also look at novel emerging instruments and methods that promise to overcome our current technological limitations and shed new light on these important structures.
Owen
Dylan M
DM
Chemical Biology Centre, Imperial College London, London, UK. dylan.owen00@imperial.ac.uk
Neil
Mark A A
MA
French
Paul M W
PM
Magee
Anthony I
AI
D001665:Binding Sites; D002477:Cells / Q000737:chemistry* / Q000648:ultrastructure*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D021962:Membrane Microdomains / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure*; D008854:Microscopy, Electron / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D015335:Molecular Probes / Q000737:chemistry; D055095:Optics and Photonics; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000502:physiology
D005456:Fluorescent Dyes; D015335:Molecular Probes