Dissecting the actin cortex density and membrane-cortex distance in living cells by super-resolution microscopy. (11th January 2017)

• Record Type: Journal Article
• Authors: Clausen, M P; Colin-York, H; Schneider, F; Eggeling, C; Fritzsche, M
• Is Part Of: Journal of physics. Volume 50:Number 6(2017)
• Publication Date: 2017-01-11
• Subjects: super-resolution microscopy -- actin cortex -- membrane-cortex interface -- plasma membrane; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aa52a1
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Nanoscale spacing between the plasma membrane and the underlying cortical actin cytoskeleton profoundly modulates cellular morphology, mechanics, and function. Measuring this distance has been a key challenge in cell biology. Current methods for dissecting the nanoscale spacing either limit themselves to complex survey design using fixed samples or rely on diffraction-limited fluorescence imaging whose spatial resolution is insufficient to quantify distances on the nanoscale. Using dual-color super-resolution STED (stimulated-emission-depletion) microscopy, we here overcome this challenge and accurately measure the density distribution of the cortical actin cytoskeleton and the distance between the actin cortex and the membrane in live Jurkat T-cells. We found an asymmetric cortical actin density distribution with a mean width of 230 (+105/−125) nm. The spatial distances measured between the maximum density peaks of the cortex and the membrane were bi-modally distributed with mean values of 50 ± 15 nm and 120 ± 40 nm, respectively. Taken together with the finite width of the cortex, our results suggest that in some regions the cortical actin is closer than 10 nm to the membrane and a maximum of 20 nm in others.