Catala-Castro, F. et al. Direct force measurements of subcellular mechanics in confinement using optical tweezers, JoVE, 2021, pdf

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Here, we review empirical and theoretical studies of how the extracellular matrix (ECM), cytoskeleton and the plasma membrane transmit mechanical force, and discuss how these concepts apply to the sense of touch.

We always left cells to recover before adhesion measurements with the AFM. Here is why. Rajib and Nico characterized the recovery time of fibroblast and HeLa cells after dissociation from their culture dish.

Surprise: Spectrin is important. Featured by NIH: http://www.ninds.nih.gov/news_and_events/news_articles/news_article_touch_05162014.htm

In essence,  physical properties of lipid bilayers are crucial for ion channel function.

Cells repel each other using a negatively charged surface coat to make space for interstitial fluid.

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As simple as this: Membrane tension influence migration by tuning formation of cell protrusion. Lowering membrane tension by knocking down membrane-csk attachment proteins such as ezrin or myosin 1, causes abberant blebbing and slower movement of the perturbed cells.

Kupffers vesicle determines left-right asymmetry in developing zebrafish embryos. We used fluorescent activated cell sorting to sort gfp-expressing forerunner cells, progenitors of the KV, and measure their adhesive properties to one another. A reduction in adhesion correlates with perturbed KV function and defects in heart development.

169, 2010.  pdf

How does migration of embryonic progenitor cells in 3D depend on adhesive properties? We used SCFS to measure the adhesive force and show that a reduction in adhesion correlates with a loss of movement directionality of developing mesodermal cells. We propose that mesendodermal cells migrate as a collective and that E-cadherin is needed to `feel’ neighbouring cells.

D. J. Muller, M. Krieg, D. Alsteens, and Y. F. Dufrene. New frontiers in atomic force microscopy: analyzing interactions from single-molecules to cells. Curr Opin Biotechnol, 20(1):4–13, 2009.pdf

Yet another review article about SCFS in cell biology.

Here we used membrane tethers pulled from living cells to measure binding kinetics of mannose-ConA bond. Due to membrane tension, a constant force acts on the bond that couples the cell membrane to the tip of an AFM cantilever. By modulating the membrane tension, and varying the pulling speed, we could adjust the force on this bond. The unbinding kinetics nicely followed the Bell model of force accelerated bond dissociation.

We used biochemical and biophysical tools to understand the role of adhesive and mechanical forces during germlayer progenitor sorting in zebrafish. Specifically, we found that hierarchiy in cortex tension predicts the spatial organization of organ progenitor during gastrulation.

cell cohesion through rab5c and e-cadherin. Dev Cell, 9(4):555–64, 2005. § shared first author pdf

Here we showed that wnt11, a signaling molecule of the non-canonical wnt pathway regulates adhesion to e-cadherin by rab-5 mediated endocytosis. The featured image shows sequential images of a cohering cell-triplet. Using SCFS, we measured cadherin-mediated adhesion down to the level of a single molecule. The article was featured in Nature Reviews MCB, Vol. 6 No 11, 2005

The first application of single cell force spectroscopy in the Muller Lab. What a start of a glorious time! We could show that the non-canonical wnt pathway influence cell adhesion to fibronectin – a surprising finding that was a featured article of the JCS issue. featured-pdf

A. Kedrov, M. Krieg, C. Ziegler, W. Kuhlbrandt, and D. J. Muller. Locating ligand binding and activation of a single antiporter. EMBO Rep, 6(7):668–74, 2005. pdf

Here we used Atomic Force Microscopy based single molecule force spectroscopy to measure the forces that stabilize the ligand binding site of a sodium-proton ion channel.