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Full-Text Articles in Life Sciences
Genetic And Physical Interactions Between The Organellar Mechanosensitive Ion Channel Homologs Msl1, Msl2, And Msl3 Reveal A Role For Inter-Organellar Communication In Plant Development, Josephine S. Lee, Margaret E. Wilson, Ryan A. Richardson, Elizabeth S. Haswell
Genetic And Physical Interactions Between The Organellar Mechanosensitive Ion Channel Homologs Msl1, Msl2, And Msl3 Reveal A Role For Inter-Organellar Communication In Plant Development, Josephine S. Lee, Margaret E. Wilson, Ryan A. Richardson, Elizabeth S. Haswell
Biology Faculty Publications & Presentations
Plant development requires communication on many levels, including between cells and between organelles within a cell. For example, mitochondria and plastids have been proposed to be sensors of environmental stress and to coordinate their re- sponses. Here we present evidence for communication between mitochondria and chloroplasts during leaf and root development, based on genetic and physical inter- actions between three Mechanosensitive channel of Small conductance-Like (MSL) proteins from Arabidopsis thaliana. MSL proteins are Arabidopsis homologs of the bac- terial Mechanosensitive channel of Small conductance (MscS), which relieves cellular osmotic pressure to protect against lysis during hypoosmotic shock. MSL1 localizes to …
Msl1 Is A Mechanosensitive Ion Channel That Dissipates Mitochondrial Membrane Potential And Maintains Redox Homeostasis In Mitochondria During Abiotic Stress, Chun Pong Lee, Grigory Maksaev, Gregory S. Jensen, Monika W. Murcha, Margaret E. Wilson, Mark Fricker, Ruediger Hell, Elizabeth S. Haswell, A Harvey Millar, Lee J. Sweetlove
Msl1 Is A Mechanosensitive Ion Channel That Dissipates Mitochondrial Membrane Potential And Maintains Redox Homeostasis In Mitochondria During Abiotic Stress, Chun Pong Lee, Grigory Maksaev, Gregory S. Jensen, Monika W. Murcha, Margaret E. Wilson, Mark Fricker, Ruediger Hell, Elizabeth S. Haswell, A Harvey Millar, Lee J. Sweetlove
Biology Faculty Publications & Presentations
Mitochondria must maintain tight control over the electrochemical gradient across their inner membrane to allow ATP synthesis while maintaining a redox-balanced electron transport chain and avoiding excessive reactive oxygen species production. However, there is a scarcity of knowledge about the ion transporters in the inner mitochondrial membrane that contribute to control of membrane potential. We show that loss of MSL1, a member of a family of mechanosensitive ion channels related to the bacterial channel MscS, leads to increased membrane potential of Arabidopsis mitochondria under specific bioenergetic states. We demonstrate that MSL1 localises to the inner mitochondrial membrane. When expressed in …
Purification Of 26s Proteasomes And Their Subcomplexes From Plants, Richard S. Marshall, David C. Gemperline, Richard D. Vierstra
Purification Of 26s Proteasomes And Their Subcomplexes From Plants, Richard S. Marshall, David C. Gemperline, Richard D. Vierstra
Biology Faculty Publications & Presentations
The 26S proteasome is a highly dynamic, multisubunit, ATP-dependent protease that plays a central role in cellular housekeeping and many aspects of plant growth and development by degrading aberrant polypeptides and key cellular regulators that are first modified by ubiquitin. Although the 26S proteasome was originally enriched from plants over 30 years ago, only recently have significant advances been made in our ability to isolate and study the plant particle. Here, we describe two robust methods for purifying the 26S proteasome and its subcomplexes from Arabidopsis thaliana; one that involves conventional chromatography techniques to isolate the complex from wild-type …
Functions Of The Arabidopsis Kinesin Superfamily Of Microtubule-Based Motor Proteins, Chuanmei Zhu, Ram Dixit
Functions Of The Arabidopsis Kinesin Superfamily Of Microtubule-Based Motor Proteins, Chuanmei Zhu, Ram Dixit
Biology Faculty Publications & Presentations
Plants possess a large number of microtubule-based kinesin motor proteins. While the kinesin-2, 3, 9, and 11 families are absent from land plants, the kinesin-7 and 14 families are greatly expanded. In addition, some kinesins are specifically present only in land plants. The distinctive inventory of plant kinesins suggests that kinesins have evolved to perform specialized functions in plants. Plants assemble unique microtubule arrays during their cell cycle, including the interphase cortical microtubule array, preprophase band, anastral spindle and phragmoplast. In this review, we explore the functions of plant kinesins from a microtubule array viewpoint, focusing mainly on Arabidopsis kinesins. …
Computer Simulation And Mathematical Models Of The Noncentrosomal Plant Cortical Microtubule Cytoskeleton, Ezgi Can Eren, Natarajan Gautam, Ram Dixit
Computer Simulation And Mathematical Models Of The Noncentrosomal Plant Cortical Microtubule Cytoskeleton, Ezgi Can Eren, Natarajan Gautam, Ram Dixit
Biology Faculty Publications & Presentations
There is rising interest in modeling the noncentrosomal cortical microtubule cytoskeleton of plant cells, particularly its organization into ordered arrays and the mechanisms that facilitate this organization. In this review, we discuss quantitative models of this highly complex and dynamic structure both at a cellular and molecular level. We report differences in methodologies and assumptions of different models as well as their controversial results. Our review provides insights for future studies to resolve these controversies, in addition to underlining the common results between various models. We also highlight the need to compare the results from simulation and mathematical models with …
Single-Molecule Analysis Of The Microtubule Cross-Linking Protein Map65-1 Reveals A Molecular Mechanism For Contact-Angle-Dependent Microtubule Bundling, Amanda Tulin, Sheri Mcclerklin, Yue Huang, Ram Dixit
Single-Molecule Analysis Of The Microtubule Cross-Linking Protein Map65-1 Reveals A Molecular Mechanism For Contact-Angle-Dependent Microtubule Bundling, Amanda Tulin, Sheri Mcclerklin, Yue Huang, Ram Dixit
Biology Faculty Publications & Presentations
Bundling of microtubules (MTs) is critical for the formation of complex MT arrays. In land plants, the interphase cortical MTs form bundles specifically following shallow-angle encounters between them. To investigate how cells select particular MT contact angles for bundling, we used an in vitro reconstitution approach consisting of dynamic MTs and the MT-cross-linking protein MAP65-1. We found that MAP65-1 binds to MTs as monomers and inherently targets antiparallel MTs for bundling. Dwell-time analysis showed that the affinity of MAP65-1 for antiparallel overlapping MTs is about three times higher than its affinity for single MTs and parallel overlapping MTs. We also …
Mscs-Like10 Is A Stretch-Activated Ion Channel From Arabidopsis Thaliana With A Preference For Anions, Grigory Maksaev, Elizabeth S. Haswell
Mscs-Like10 Is A Stretch-Activated Ion Channel From Arabidopsis Thaliana With A Preference For Anions, Grigory Maksaev, Elizabeth S. Haswell
Biology Faculty Publications & Presentations
Like many other organisms, plants are capable of sensing and responding to mechanical stimuli such as touch, osmotic pressure, and gravity. One mechanism for the perception of force is the activation of mechanosensitive (or stretch-activated) ion channels, and a number of mechanosensitive channel activities have been described in plant membranes. Based on their homology to the bacterial mechanosensitive channel MscS, the 10 MscS-Like (MSL) proteins of Arabidopsis thaliana have been hypothesized to form mechanosensitive channels in plant cell and organelle membranes. However, definitive proof that MSLs form mechanosensitive channels has been lacking. Here we used single-channel patch clamp electrophysiology to …
Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit
Single Molecule Analysis Of The Arabidopsis Fra1 Kinesin Shows That It Is A Functional Motor Protein With Unusually High Processivity, Chuanmei Zhu, Ram Dixit
Biology Faculty Publications & Presentations
The Arabidopsis FRA1 kinesin contributes to the organization of cellulose microfibrils through an unknown mechanism. The cortical localization of this kinesin during interphase raises the possibility that it transports cell wall-related cargoes along cortical microtubules that either directly or indirectly influence cellulose microfibril patterning. To determine whether FRA1 is an authentic motor protein, we combined bulk biochemical assays and single molecule fluorescence imaging to analyze the motor properties of recombinant, GFP-tagged FRA1 containing the motor and coiled-coil domains (designated as FRA1(707)–GFP). We found that FRA1(707)–GFP binds to microtubules in an ATP-dependent manner and that its ATPase activity is dramatically stimulated …
A Three-Dimensional Computer Simulation Model Reveals The Mechanisms For Self-Organization Of Plant Cortical Microtubules Into Oblique Arrays, Ezgi Can Eren, Ram Dixit, Natarajan Gautam
A Three-Dimensional Computer Simulation Model Reveals The Mechanisms For Self-Organization Of Plant Cortical Microtubules Into Oblique Arrays, Ezgi Can Eren, Ram Dixit, Natarajan Gautam
Biology Faculty Publications & Presentations
The noncentrosomal cortical microtubules (CMTs) of plant cells self-organize into a parallel three-dimensional (3D) array that is oriented transverse to the cell elongation axis in wild-type plants and is oblique in some of the mutants that show twisted growth. To study the mechanisms of CMT array organization, we developed a 3D computer simulation model based on experimentally observed properties of CMTs. Our computer model accurately mimics transverse array organization and other fundamental properties of CMTs observed in rapidly elongating wild-type cells as well as the defective CMT phenotypes observed in the Arabidopsis mor1-1 and fra2 mutants. We found that CMT …
Establishment Of Polarity During Organization Of The Acentrosomal Plant Cortical Microtubule Array, Ram Dixit, Eric Chang, Richard Cyr
Establishment Of Polarity During Organization Of The Acentrosomal Plant Cortical Microtubule Array, Ram Dixit, Eric Chang, Richard Cyr
Biology Faculty Publications & Presentations
The plant cortical microtubule array is a unique acentrosomal array that is essential for plant morphogenesis. To understand how this array is organized, we exploited the microtubule (+)-end tracking activity of two Arabidopsis EB1 proteins in combination with FRAP (fluorescence recovery after photobleaching) experiments of GFP-tubulin to examine the relationship between cortical microtubule array organization and polarity. Significantly, our observations show that the majority of cortical microtubules in ordered arrays, within a particular cell, face the same direction in both Arabidopsis plants and cultured tobacco cells. We determined that this polar microtubule coalignment is at least partially due to a …