Search bioRxiv⌕ Search

bioRxiv · 10.1101/604488

Disruption of membrane cholesterol organization impairs the concerted activity of PIEZO1 channel clusters

Abstract

The human mechanosensitive ion channel PIEZO1 is gated by membrane tension and regulates essential biological processes such as vascular development and erythrocyte volume homeostasis. Currently, little is known about PIEZO1 plasma membrane localization and organization. Using a PIEZO1-GFP fusion protein, we investigated whether cholesterol enrichment or depletion by methyl-{beta}-Cyclodextrin (MBCD) and disruption of membrane cholesterol organization by dynasore affects PIEZO1-GFPs response to mechanical force. Electrophysiological recordings in the cell-attached configuration revealed that MBCD caused a rightward shift in the PIEZO1-GFP pressure-response curve, increased channel latency in response to mechanical stimuli and markedly slowed channel inactivation. The same effects were seen in native PIEZO1 in N2A cells. STORM super-resolution imaging revealed that, at the nano-scale, PIEZO1-GFP channels in the membrane associate as clusters sensitive to membrane manipulation. Both cluster distribution and diffusion rates were affected by treatment with MBCD (5 mM). Supplementation of poly-unsaturated fatty acids appeared to sensitize the PIEZO1-GFP response to applied pressure. Together, our results indicate that PIEZO1 function is directly dependent on the membrane mechanical properties and lateral organization of membrane cholesterol domains which coordinates the concerted activity of PIEZO1 channels.\n\nSUMMARYThe essential mammalian mechanosensitive channel PIEZO1 organizes in the plasma membrane into nanometric clusters which depend on the integrity of cholesterol domains to rapidly detect applied force and especially inactivate syncronously, the most commonly altered feature of PIEZO1 in pathology.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ridone, P., Pandzic, E., Vassalli, M., Cox, C. D., Macmillan, A., Gottlieb, P. A., Martinac, B.. 2019-04-11. Disruption of membrane cholesterol organization impairs the concerted activity of PIEZO1 channel clusters. https://doi.org/10.1101/604488

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Amyloid stability and condensate material properties independently govern the hnRNPA2 condensate to fibril transition

hnRNPA2 is a component of cellular membraneless organelles many of which contain RNA and RNA-binding proteins (RBPs). RBPs frequently contain low-complexity domains (LCDs) that can also assemble into amyloid fibrils. Fibrils isolated from patients with frontotemporal lobar degeneration contain ordered segments of these LCDs and disease-associated mutations can enhance the homotypic interactions that promote aggregation. Although previous studies have largely examined the condensate-to-fibril transition by altering condensate stability, how amyloid structure governs this process remains poorly understood. Here, we show that the hnRNPA2 LCD forms a reproducible fibril fold and by combining structure-guided thermodynamic profiling, peptide design, mutagenesis and in vitro characterization under conditions with (two-phase) and without (one-phase) condensates, we define the molecular determinants of its assembly. We identify an aromatic triad within the fibril core that controls fibril formation kinetics and thermodynamic stability. Mutational analysis further reveals that condensate stability and fibril stability are largely independent. Finally, microrheology linked reduced condensate viscosity to faster fibril formation, supporting a role for condensate material properties in regulating aggregation kinetics. Together, these findings support a model in which the condensate-to-fibril transition is governed by the interplay between a disordered ''fuzzy coat'' and a fibril-forming aromatic triad within hnRNPA2. This work provides a structural framework for understanding how condensates can transition into amyloid assemblies.

biophysics↗

hAM-pe soluble extract increases human keratinocyte HaCaT cell-line mobility in scratch assays

We have studied the impact of human amniotic membrane (hAM-pe) on wound closing speed in a scratch assay of human keratinocytes (HaCaT). Though not without limitations, scratch assays are useful for studying collective cellular displacement as a model of wound healing. We show that the treatment is effective in decreasing the average time that the cells need to completely close the wound, in agreement with previous \emph{in vivo} experiments. We developed an automated segmentation software, and verified that a linear fit, though not completely describing the wound edge dynamics, is a robust method for comparing treatments and control measurements. By tracking the individual motion of a subset of cells, we found that individual treatment does not cause an increase in individual speed enough to explain the effect of the treatment at the collective (wound edge) level. Instead, the mean squared displacement and numerical simulations of a simple model of interacting active Brownian particles support the view that the main effect of the treatment at the individual level is to increase the persistence of cellular motion.

biophysics↗

Temperature-dependent Fano resonance in Microtubules and Tubulin investigated with Spontaneous Raman Spectroscopy

Microtubules are self-assembled biological hollow nanotubes composed by protein tubulin. They are essential for many biological functions, including cell motility, cell division, and act as intracellular track for organelle transport. In turn, through dynamic assembly and disassembly, they form spindle fibers for chromosome segregation during mitosis and meiosis. In this paper, we have measured the Raman spectra of microtubules and their constituent protein tubulin in dry powder form for a range of temperatures, from nitrogen liquid T=77 K up to room and physiological temperature T=310 K, to determine if molecular bond vibrations present potential Fano resonance asymmetry. We have found nontrivial persistence of Fano resonances, q<5, at room and physiological temperatures for some specific vibrational modes.

biophysics↗