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Full-Text Articles in Cell Anatomy
Cryo-Em Structure Of Mechanosensitive Channel Ynai Using Sma2000: Challenges And Opportunities, Claudio Catalano, Danya Ben-Hail, Weihua Qiu, Paul Blount, Amedee Des Georges, Youzhong Guo
Cryo-Em Structure Of Mechanosensitive Channel Ynai Using Sma2000: Challenges And Opportunities, Claudio Catalano, Danya Ben-Hail, Weihua Qiu, Paul Blount, Amedee Des Georges, Youzhong Guo
Publications and Research
Mechanosensitive channels respond to mechanical forces exerted on the cell membrane and play vital roles in regulating the chemical equilibrium within cells and their environment. Highresolution structural information is required to understand the gating mechanisms of mechanosensitive channels. Protein-lipid interactions are essential for the structural and functional integrity of mechanosensitive channels, but detergents cannot maintain the crucial native lipid environment for purified mechanosensitive channels. Recently, detergent-free systems have emerged as alternatives for membrane protein structural biology. This report shows that while membrane-active polymer, SMA2000, could retain some native cell membrane lipids on the transmembrane domain of the mechanosensitive-like YnaI channel, …
Unconventional Constituents And Shared Molecular Architecture Of The Melanized Cell Wall Of C. Neoformans And Spore Wall Of S. Cerevisiae, Christine Chrissian, Coney Pei-Chin Lin, Emma Camacho, Arturo Casadevall, Aaron M. Neiman, Ruth E. Stark
Unconventional Constituents And Shared Molecular Architecture Of The Melanized Cell Wall Of C. Neoformans And Spore Wall Of S. Cerevisiae, Christine Chrissian, Coney Pei-Chin Lin, Emma Camacho, Arturo Casadevall, Aaron M. Neiman, Ruth E. Stark
Publications and Research
The fungal cell wall serves as the interface between the cell and the environment. Fungal cell walls are composed largely of polysaccharides, primarily glucans and chitin, though in many fungi stress-resistant cell types elaborate additional cell wall structures. Here, we use solid-state nuclear magnetic resonance spectroscopy to compare the architecture of cell wall fractions isolated from Saccharomyces cerevisiae spores and Cryptococcus neoformans melanized cells. The specialized cell walls of these two divergent fungi are highly similar in composition. Both use chitosan, the deacetylated derivative of chitin, as a scaffold on which a polyaromatic polymer, dityrosine and melanin, respectively, is assembled. …
Inhibition Of Mitochondrial Permeability Transition By Deletion Of The Ant Family And Cypd, Jason Karch, Michael J. Bround, Hadi Khalil, Michelle A. Sargent, Nadina Latchman, Naohiro Terada, Pablo M. Peixoto, Jeffery D. Molkentin
Inhibition Of Mitochondrial Permeability Transition By Deletion Of The Ant Family And Cypd, Jason Karch, Michael J. Bround, Hadi Khalil, Michelle A. Sargent, Nadina Latchman, Naohiro Terada, Pablo M. Peixoto, Jeffery D. Molkentin
Publications and Research
The mitochondrial permeability transition pore (MPTP) has resisted molecular identification. The original model of the MPTP that proposed the adenine nucleotide translocator (ANT) as the inner membrane pore-forming component was challenged when mitochondria from Ant1/2 double null mouse liver still had MPTP activity. Because mice express three Ant genes, we reinvestigated whether the ANTs comprise the MPTP. Liver mitochondria from Ant1, Ant2, and Ant4 deficient mice were highly refractory to Ca2+-induced MPTP formation, and when also given cyclosporine A (CsA), the MPTP was completely inhibited. Moreover, liver mitochondria from mice with quadruple deletion of Ant1, Ant2, Ant4, and Ppif (cyclophilin …
Cryo-Em Structure Of The Human Ferritin–Transferrin Receptor 1 Complex, Linda Celeste Montemiglio, Claudia Testi, Pierpaolo Ceci, Elisabetta Falvo, Martina Pitea, Carmelinda Savino, Alessandro Arcovito, Giovanna Peruzzi, Paola Baiocco, Filippo Mancia, Alberto Boffi, Amédée Des Georges, Beatrice Vallone
Cryo-Em Structure Of The Human Ferritin–Transferrin Receptor 1 Complex, Linda Celeste Montemiglio, Claudia Testi, Pierpaolo Ceci, Elisabetta Falvo, Martina Pitea, Carmelinda Savino, Alessandro Arcovito, Giovanna Peruzzi, Paola Baiocco, Filippo Mancia, Alberto Boffi, Amédée Des Georges, Beatrice Vallone
Publications and Research
Human transferrin receptor 1 (CD71) guarantees iron supply by endocytosis upon binding of iron-loaded transferrin and ferritin. Arenaviruses and the malaria parasite exploit CD71 for cell invasion and epitopes on CD71 for interaction with transferrin and pathogenic hosts were identified. Here, we provide the molecular basis of the CD71 ectodomain-human ferritin interaction by determining the 3.9 Å resolution single-particle cryo-electron microscopy structure of their complex and by validating our structural findings in a cellular context. The contact surfaces between the heavy-chain ferritin and CD71 largely overlap with arenaviruses and Plasmodium vivax binding regions in the apical part of the receptor …
Advances In Geometric Techniques For Analyzing Blebbing In Chemotaxing Dictyostelium Cells, Zully Santiago, John Loustau, David Meretzky, Devarshi Rawal, Derrick Brazill
Advances In Geometric Techniques For Analyzing Blebbing In Chemotaxing Dictyostelium Cells, Zully Santiago, John Loustau, David Meretzky, Devarshi Rawal, Derrick Brazill
Publications and Research
We present a technical platform that allows us to monitor and measure cortex and membrane dynamics during bleb-based chemotaxis. Using D. discoideum cells expressing LifeAct-GFP and crawling under agarose containing RITC-dextran, we were able to simultaneously visualize the actin cortex and the cell membrane throughout bleb formation. Using these images, we then applied edge detect to generate points on the cell boundary with coordinates in a coordinate plane. Then we fitted these points to a curve with known x and y coordinate functions. The result was to parameterize the cell outline. With the parameterization, we demonstrate how to compute data …
Unravelling The Structure Of Glycosyl Cations Via Cold-Ion Infrared Spectroscopy, Eike Mucha, Mateusz Marianski, Fei-Fei Xu, Daniel A. Thomas, Gerard Meijer, Gert Von Helden, Peter H. Seeberger, Kevin Pagel
Unravelling The Structure Of Glycosyl Cations Via Cold-Ion Infrared Spectroscopy, Eike Mucha, Mateusz Marianski, Fei-Fei Xu, Daniel A. Thomas, Gerard Meijer, Gert Von Helden, Peter H. Seeberger, Kevin Pagel
Publications and Research
Glycosyl cations are the key intermediates during the glycosylation reaction that covalently links building blocks during the synthetic assembly of carbohydrates. The exact structure of these ions remained elusive due to their transient and short-lived nature. Structural insights into the intermediate would improve our understanding of the reaction mechanism of glycosidic bond formation. Here, we report an in-depth structural analysis of glycosyl cations using a combination of cold-ion infrared spectroscopy and first-principles theory. Participating C2 protective groups form indeed a covalent bond with the anomeric carbon that leads to C1-bridged acetoxonium-type structures. The resulting bicyclic structure strongly distorts the ring, …
Lim Protein Ajuba Associates With The Rpa Complex Through Direct Cell Cycle-Dependent Interaction With The Rpa70 Subunit, Sandy Fowler, Pascal Maguin, Sampada Kalan, Diego Loayza
Lim Protein Ajuba Associates With The Rpa Complex Through Direct Cell Cycle-Dependent Interaction With The Rpa70 Subunit, Sandy Fowler, Pascal Maguin, Sampada Kalan, Diego Loayza
Publications and Research
DNA damage response pathways are essential for genome stability and cell survival. Specifically, the ATR kinase is activated by DNA replication stress. An early event in this activation is the recruitment and phosphorylation of RPA, a single stranded DNA binding complex composed of three subunits, RPA70, RPA32 and RPA14. We have previously shown that the LIM protein Ajuba associates with RPA, and that depletion of Ajuba leads to potent activation of ATR. In this study, we provide evidence that the Ajuba-RPA interaction occurs through direct protein contact with RPA70, and that their association is cell cycle-regulated and is reduced upon …
Bax And Bak Function As The Outer Membrane Component Of The Mitochondrial Permeability Pore In Regulating Necrotic Cell Death In Mice, Jason Karch, Jennifer Q. Kwong, Adam R. Burr, Michelle A. Sargent, John W. Elrod, Pablo M. Peixoto, Sonia Martinez-Caballero, Hanna Osinskka, Emily H-Y Cheng, Jeffrey Robbins, Kathleen W. Kinnally, Jeffrey D. Molkentin
Bax And Bak Function As The Outer Membrane Component Of The Mitochondrial Permeability Pore In Regulating Necrotic Cell Death In Mice, Jason Karch, Jennifer Q. Kwong, Adam R. Burr, Michelle A. Sargent, John W. Elrod, Pablo M. Peixoto, Sonia Martinez-Caballero, Hanna Osinskka, Emily H-Y Cheng, Jeffrey Robbins, Kathleen W. Kinnally, Jeffrey D. Molkentin
Publications and Research
A critical event in ischemia-based cell death is the opening of the mitochondrial permeability transition pore (MPTP). However, the molecular identity of the components of the MPTP remains unknown. Here, we determined that the Bcl-2 family members Bax and Bak, which are central regulators of apoptotic cell death, are also required for mitochondrial pore-dependent necrotic cell death by facilitating outer membrane permeability of the MPTP. Loss of Bax/Bak reduced outer mitochondrial membrane permeability and conductance without altering inner membrane MPTP function, resulting in resistance to mitochondrial calcium overload and necrotic cell death. Reconstitution with mutants of Bax that cannot oligomerize …