Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 8: Poster Session Ia
BP 8.9: Poster
Monday, March 18, 2024, 18:00–20:30, Poster C
Membrane Stiffness and Formation of Microtentacles — •Yannic Veit1, Lucina Kainka1, Christoph Anton1, and Franziska Lautenschläger1,2 — 1Department of Experimental Physics, Saarland University, Saarbrücken, Germany — 2Center for Biophysics, Saarbrücken, Germany
Microtentacles (McTNs) are microtubule-based membrane protrusions. They are found in circulating tumour cells (CTCs) and are assumed to promote reattachment of the CTCs to the vessel walls and facilitate the extravasation from the blood stream.
We previously found that McTNs grow from actin-rich sites (actin patches). There is a force balance between the microtubules and the cell barrier, which consists of the actin cortex and the cell membrane. During the formation of microtentacles, that barrier exerts a counterforce depending on its stiffness on the microtubules. This led us to a question: Does decreased actin patch area decrease membrane stiffness and influence McTN formation?
To disentagle the influence of the two components of the barrier, we tackled actin directly by depolymerisation using latrunculin A, and the membrane stiffness itself by depleting it of cholesterol with methyl-beta-cyclodextrin. The membrane stiffness was quantified via tether rupturing using atomic force microscopy.
We found that decreasing the actin patch area decreases the membrane stiffness while depleting the membranes of cholesterol increases the stiffness. We found that an increase in membrane stiffness inhibits microtentacle formation.
Keywords: Microtentacles; Microtubules; Actin; Membrane Stiffness; Cholesterol Depletion