Browsing by Author "Panda, Yogishree Arabinda"

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Open Access
Data MembraneTension HeLa in mitosis
(Technische Universität Dresden, 2025-02-11) Fischer-Friedrich, Elisabeth; Panda, Yogishree Arabinda
In this project, we were investigating the membrane tension in mitotically arrested HeLa cells using two different methods: the optical membrane tension sensor FliptR and membrane tether forces. FliptR is a fluorescent dye that localizes to the plasma membrane. Perfoming FLIM on the plasma membrane fluorescence signal, we fitted fluorescence lifetimes as a measure of membrane tension. Further, coated tips of an pyramidal AFM cantilever (Bruker MLCT) were used to pull membrane tethers. The full description of the Methods is in the uploaded manuscript draft "PandaEtAl.pdf" contained in PaperArabinda_05Feb2025.zip The microscopy/AFM data used for analysis and generation of the figures in this manuscript draft are uploaded in this archive. Figure numbers in the naming of the folders are corresponding to the figure numbers in this manuscript draft and not to figure numbers in a potentially updated later version of the manuscript.
Open Access
Localized actin cortex perturbation generates cell-scale membrane tension gradients
(Technische Universität Dresden, 2026-10-27) Panda, Yogishree Arabinda
Membrane tension is a key mechanical regulator of cell signaling, morphology, and division. Whether cells can sustain spatial gradients in membrane tension, or whether such asymmetries are rapidly dissipated by long-range tension propagation, remains actively debated. Here, we use the tension-sensitive fluorescent probe FliptR to directly measure changes in in-plane membrane tension following localized optogenetic activation of RhoA in mitotic HeLa cells. We find that local RhoA activation induces a sustained, cell-scale gradient in FliptR lifetime, consistent with a cell-scale in-plane membrane tension gradient and tension elevation on the non-activated side. This gradient depends on an intact actin and microtubule cytoskeleton and is accompanied by polarized cytoskeletal remodeling, with cortical F-actin enrichment at the activation site and asymmetric microtubule growth on the opposite side. AFM tether-force measurements reveal increased tether forces at the activated side, indicating locally enhanced membrane–cortex coupling. A coarse-grained membrane chemical-potential model explains how spatially heterogeneous membrane–cortex coupling can maintain such gradients. Together, our findings show that cells can actively generate and sustain spatially patterned mechanical states through localized cytoskeletal signaling.