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Full-Text Articles in Life Sciences

Charged Pore-Lining Residues Are Required For Normal Channel Kinetics In The Eukaryotic Mechanosensitive Ion Channel Msl1, Angela M. Schlegel, Elizabeth S. Haswell Dec 2020

Charged Pore-Lining Residues Are Required For Normal Channel Kinetics In The Eukaryotic Mechanosensitive Ion Channel Msl1, Angela M. Schlegel, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

Mechanosensitive (MS) ion channels are widespread mechanisms for cellular mechanosensation that can be directly activated by increasing membrane tension. The well-studied MscS family of MS ion channels is found in bacteria, archaea, and plants. MscS-Like (MSL)1 is localized to the inner mitochondrial membrane of Arabidopsis thaliana, where it is required for normal mitochondrial responses to oxidative stress. Like Escherichia coli MscS, MSL1 has a pore-lining helix that is kinked. However, in MSL1 this kink is comprised of two charged pore-lining residues, R326 and D327. Using single-channel patch-clamp electrophysiology in E. coli, we show that altering the size and …


Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew Sep 2020

Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm−2) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …


Structural Mechanism For Gating Of A Eukaryoticmechanosensitive Channel Of Small Conductance, Zengqin Deng, Grigory Maksaev, Angela M. Schlegel, Jingying Zhang, Michael Rau, James A.J. Fitzpatrick, Elizabeth S. Haswell, Peng Yuan Jul 2020

Structural Mechanism For Gating Of A Eukaryoticmechanosensitive Channel Of Small Conductance, Zengqin Deng, Grigory Maksaev, Angela M. Schlegel, Jingying Zhang, Michael Rau, James A.J. Fitzpatrick, Elizabeth S. Haswell, Peng Yuan

Biology Faculty Publications & Presentations

Mechanosensitive ion channels transduce physical force into electrochemical signaling that underlies an array of fundamental physiological processes, including hearing, touch, proprioception, osmoregulation, and morphogenesis. The mechanosensitive channels of small conductance (MscS) constitute a remarkably diverse superfamily of channels critical for management of osmotic pressure. Here, we present cryo-electron microscopy structures of a MscS homolog from Arabidopsis thaliana, MSL1, presumably in both the closed and open states. The heptameric MSL1 channel contains an unusual bowl-shaped transmembrane region, which is reminiscent of the evolutionarily and architecturally unrelated mechanosensitive Piezo channels. Upon channel opening, the curved transmembrane domain of MSL1 flattens and expands. …


The Mechanosensitive Ion Channel Msl10 Potentiates Responses To Cell Swelling In Arabidopsis Seedlings, Debarati Basu, Elizabeth S. Haswell Jul 2020

The Mechanosensitive Ion Channel Msl10 Potentiates Responses To Cell Swelling In Arabidopsis Seedlings, Debarati Basu, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

The ability to respond to unanticipated increases in volume is a fundamental property of cells, essential for cellular integrity in the face of osmotic challenges. Plants must manage cell swelling during flooding, rehydration, and pathogen invasion-but little is known about the mechanisms by which this occurs. It has been proposed that plant cells could sense and respond to cell swelling through the action of mechanosensitive ion channels. Here, we characterize a new assay to study the effects of cell swelling on Arabidopsis thaliana seedlings and to test the contributions of the mechanosensitive ion channel MscS-like10 (MSL10). The assay incorporates both …


Plant Biomechanics: No Pain, No Gain For Birch Tree Stems, A. M. Schlegel, E. S. Haswell Feb 2020

Plant Biomechanics: No Pain, No Gain For Birch Tree Stems, A. M. Schlegel, E. S. Haswell

Biology Faculty Publications & Presentations

Allometric relationships between organism size and shape are often described in developmental or evolutionary terms. A new study characterizes a collapsing birch tree mutant and provides a genetic entry point into the biomechanical control of tree allometry.