Fast molecular tracking maps nanoscale dynamics of plasma membrane lipids

We describe an optical method capable of tracking a single fluorescent molecule with a flexible choice of high spatial accuracy (~10–20 nm standard deviation or ~20–40 nm full-width-at-half-maximum) and temporal resolution (< 1 ms). The fluorescence signal during individual passages of fluorescent molecules through a spot of excitation light allows the sequential localization and thus spatio-temporal tracking of the molecule if its fluorescence is collected on at least three separate point detectors arranged in close proximity. We show two-dimensional trajectories of individual, small organic dye labeled lipids diffusing in the plasma membrane of living cells and directly observe transient events of trapping on < 20 nm spatial scales. The trapping is cholesterol-assisted and much more pronounced for a sphingo- than for a phosphoglycero-lipid, with average trapping times of ∼15 ms and < 4 ms, respectively. The results support previous STED nanoscopy measurements and suggest that, at least for nontreated cells, the transient interaction of a single lipid is confined to macromolecular dimensions. Our experimental approach demonstrates that fast molecular movements can be tracked with minimal invasion, which can reveal new important details of cellular nano-organization.


Published in:
Proceedings of the National Academy of Sciences, 107, 15, 6829-6834
Year:
2010
Publisher:
National Academy of Sciences
ISSN:
1091-6490
Keywords:
Laboratories:




 Record created 2010-11-19, last modified 2018-03-17

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107 Fast molecular tracking maps nanoscale dynamics of plasma membrane lipids - Download fulltextPDF
107 Fast molecular tracking maps nanoscale dynamics of plasma membrane lipids.SI - Download fulltextPDF
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