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| Open AccessCryo-EM structure and B-factor refinement with ensemble representation
Cryo-EM is the go-to method for visualizing large, flexible biomolecules. Here, authors introduce a new Gaussian mixture modelling method for cryo-EM modelling tasks, including refinement, composite map generation and ensemble representation.
- Joseph G. Beton
- , Thomas Mulvaney
- & Maya Topf
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Article
| Open AccessConformational coupling of the sialic acid TRAP transporter HiSiaQM with its substrate binding protein HiSiaP
Tripartite ATP-independent periplasmic (TRAP) transporters use an extra substrate binding protein to transport a variety of substrates in bacteria and archaea. Here the authors use a disulfide engineering approach to lock the TRAP transporter HiSiaPQM from H. influenzae in different conformational states for characterisation.
- Martin F. Peter
- , Jan A. Ruland
- & Gregor Hagelueken
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Article
| Open AccessMechanism of anion exchange and small-molecule inhibition of pendrin
Here the authors report structures of pendrin, an anion exchanger, in complex with its substrate Cl−, I−, or HCO3−, which reveal two anion binding sites in each protomer. The authors also identify binding sites of a pendrin inhibitor, niflumic acid.
- Lie Wang
- , Anthony Hoang
- & Ming Zhou
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Article
| Open AccessPIEZO1 loss-of-function compound heterozygous mutations in the rare congenital human disorder Prune Belly Syndrome
PIEZO1 is a mechanosensitive ion channel. Here, authors identify PIEZO1 human mutations in Prune Belly Syndrome. At a single molecule level these mutations exhibit loss-of-function characteristics.
- Nathalia G. Amado
- , Elena D. Nosyreva
- & Ruhma Syeda
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Article
| Open AccessTon motor conformational switch and peptidoglycan role in bacterial nutrient uptake
Gram-negative bacteria rely on the Ton system for nutrient uptake. Here, authors uncover how the ExbD protein acts as a conformational switch and the function of peptidoglycan in order to energize this transport process across the outer membrane.
- Maximilian Zinke
- , Maylis Lejeune
- & Nadia Izadi-Pruneyre
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| Open AccessDCAF1-based PROTACs with activity against clinically validated targets overcoming intrinsic- and acquired-degrader resistance
Targeted protein degradation (TPD) is a key modality for drug discovery. Here the authors present the discovery and analysis of reversible DCAF1-PROTACs, which show efficacy in cellular environments resistant to VHL-PROTACs or with acquired resistance to CRBN-PROTACs.
- Martin Schröder
- , Martin Renatus
- & Claudio R. Thoma
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Article
| Open AccessThe juxtamembrane linker of synaptotagmin 1 regulates Ca2+ binding via liquid-liquid phase separation
Synaptotagmin (syt) 1 is a calcium sensor for neuronal exocytosis. Here, the authors show that the juxtamembrane linker of this integral membrane protein negatively regulates its calcium sensing activity by mediating self-association via liquid-liquid phase separation.
- Nikunj Mehta
- , Sayantan Mondal
- & Edwin R. Chapman
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Article
| Open AccessExperimental determination and mathematical modeling of standard shapes of forming autophagosomes
Autophagosome formation involves membrane morphological changes. Here, authors statistically determined average shapes of forming autophagosomes from 3D electron micrographs and established a theoretical model that quantitatively reproduces them.
- Yuji Sakai
- , Satoru Takahashi
- & Noboru Mizushima
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Article
| Open AccessLipid nanodisc scaffold and size alter the structure of a pentameric ligand-gated ion channel
The authors show that lipid nanodiscs of different scaffold type and size alter the structure of the pentameric ligand-gated ion channel, ELIC. The results suggest that nanodisc selection is an important consideration for structural studies of membrane proteins.
- Vikram Dalal
- , Mark J. Arcario
- & Wayland W. L. Cheng
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Article
| Open AccessAllosteric control of dynamin-related protein 1 through a disordered C-terminal Short Linear Motif
Drp1 is the master regulator of mitochondrial and peroxisomal fission. Here, the authors show that a C-terminal intrinsically disordered motif, named the CT-SLiM, constitutes an allosteric switch that controls Drp1 structure, assembly, and function.
- Isabel Pérez-Jover
- , Kristy Rochon
- & Rajesh Ramachandran
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Article
| Open AccessDynamic stability of Sgt2 enables selective and privileged client handover in a chaperone triad
Newly synthesized tail-anchored membrane proteins (TAs) are relayed in a chaperone triad, Hsp70, Sgt2, and Get3, for delivery to the endoplasmic reticulum. Here, the authors show how the conformational dynamics of the cochaperone Sgt2 generates a decision point to enable efficient and selective TA targeting.
- Hyunju Cho
- , Yumeng Liu
- & Shu-ou Shan
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Article
| Open AccessMolecular basis of the inositol deacylase PGAP1 involved in quality control of GPI-AP biogenesis
The inositol deacylase PGAP1 initiates glycolipid remodeling required for GPI-AP sorting and secretion. Here, authors capture three PGAP1 states in a lipid environment and with products, revealing mechanisms for substrate selectivity and catalysis.
- Jingjing Hong
- , Tingting Li
- & Dianfan Li
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Article
| Open AccessStructural heterogeneity of the ion and lipid channel TMEM16F
TMEM16F is a transmembrane protein that facilitates passive phospholipid transbilayer movement and ion conduction across membranes. Here, authors reveal a structural heterogeneity which is possibly linked to TMEM16F unique dual function.
- Zhongjie Ye
- , Nicola Galvanetto
- & Arin Marchesi
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Article
| Open AccessSelective blockade of Cav1.2 (α1C) versus Cav1.3 (α1D) L-type calcium channels by the black mamba toxin calciseptine
L-type voltage-gated calcium channels are involved in multiple physiological functions. Here the authors identify calciseptine, a toxin purified from black mamba venom, as a selective inhibitor of Cav1.2 L-type Ca2+ channels.
- Pietro Mesirca
- , Jean Chemin
- & Joël Nargeot
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Article
| Open AccessMolecular basis of human trace amine-associated receptor 1 activation
hTA1 is a drug target for several neuropsychiatric disorders. Using cryo-EM and pharmacological assays, the authors illuminate hTA1’s similarity to neurotransmitter receptors and discover that the antipsychotic asenapine potently activates the receptor.
- Gregory Zilberg
- , Alexandra K. Parpounas
- & Daniel Wacker
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Article
| Open AccessForce transmission by retrograde actin flow-induced dynamic molecular stretching of Talin
Focal adhesion proteins transmit intracellular forces to the extracellular matrix (ECM). Here, the authors show a force transmission by elastic transient clutch of Talin between ECM and constantly flowing F-actin at focal adhesions.
- Sawako Yamashiro
- , David M. Rutkowski
- & Naoki Watanabe
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Article
| Open AccessVoltage sensors of a Na+ channel dissociate from the pore domain and form inter-channel dimers in the resting state
It is believed that voltage sensor domains (VSD) of voltage-gated Na+ channels are always attached to the channel. Here, authors find that VSDs detach from the channel to form inter-channel dimers.
- Ayumi Sumino
- , Takashi Sumikama
- & Katsumasa Irie
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Article
| Open AccessBlue-shift photoconversion of near-infrared fluorescent proteins for labeling and tracking in living cells and organisms
Photolabeling of intracellular molecules is an invaluable approach to study multiple cellular processes. Here, the authors report on the near-infrared to far-red photoconversion in the miRFP family of fluorescent proteins, which enables photolabeling entirely performed in the near-infrared range.
- Francesca Pennacchietti
- , Jonatan Alvelid
- & Ilaria Testa
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Article
| Open AccessLocal energetic frustration conservation in protein families and superfamilies
Energetic local frustration in proteins may have been positively selected by evolution when related to function such as ligand binding, allostery and other. Here the authors present a methodology to analyze local frustration patterns within protein families and superfamilies.
- Maria I. Freiberger
- , Victoria Ruiz-Serra
- & Alfonso Valencia
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| Open AccessMolecular basis and cellular functions of vinculin-actin directional catch bonding
This study provides insights into the directional catch bonding of the linker protein vinculin by elucidating the molecular basis of mechanical reinforcement as well as unveiling its key role in subcellular organization and cellular processes.
- Venkat R. Chirasani
- , Mohammad Ashhar I. Khan
- & Sharon L. Campbell
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| Open AccessHydrogels with tunable mechanical plasticity regulate endothelial cell outgrowth in vasculogenesis and angiogenesis
It is vital to unveil the effects of extracellular matrix cues on endothelial cell (EC) outgrowth for desirably governing vasculature formation, but the role of matrix plasticity on EC outgrowth is elusive. Here, the authors develop hydrogels with tunable mechanical plasticity independent of stiffness, and elucidate the plasticity-mediated responses of ECs during vasculogenesis and angiogenesis.
- Zhao Wei
- , Meng Lei
- & Feng Xu
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Article
| Open AccessHomo- and hetero-dimeric subunit interactions set affinity and efficacy in metabotropic glutamate receptors
The molecular basis of functional diversity between obligatorily dimeric mGluRs is not understood. The authors show that functional differences typically attributed to differences in the agonist binding pocket emerge from differences between homomeric and heteromeric Group II and III Gi-coupled mGluRs in dimerization interface interactions.
- Chris Habrian
- , Naomi Latorraca
- & Ehud Y. Isacoff
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Article
| Open AccessCENP-A and CENP-B collaborate to create an open centromeric chromatin state
Centromeres are defined by the histone variant CENP-A. Using single-molecule fluorescence and cryoEM, this study shows that CENP-A and the centromeric protein CENP-B collaborate to create dynamic and open chromatin, aiding centromeric factor binding.
- Harsh Nagpal
- , Ahmad Ali-Ahmad
- & Beat Fierz
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Article
| Open AccessSingle-photon microscopy to study biomolecular condensates
The wide variety of cellular processes involving biomolecular condensation makes their quantification a challenging task. Here, the authors present an integrated platform based on single-photon microscopy to study complex biomolecular processes.
- Eleonora Perego
- , Sabrina Zappone
- & Giuseppe Vicidomini
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Article
| Open AccessNonuniversal impact of cholesterol on membranes mobility, curvature sensing and elasticity
Cholesterol both thickens and condenses membranes, yet it also softens them under certain conditions. Here, authors uncover cholesterol’s dual role in the delicate balance of rigidity and flexibility in membranes, crucial for diverse biological functions.
- Matthias Pöhnl
- , Marius F. W. Trollmann
- & Rainer A. Böckmann
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Article
| Open AccessConformational plasticity of RAS Q61 family of neoepitopes results in distinct features for targeted recognition
The authors use an integrative structural biology approach to elucidate molecular features of the RAS Q61 family of public tumor antigens. This information can be used to develop targeted therapeutics to combat a range of cancers.
- Andrew C. McShan
- , David Flores-Solis
- & Nikolaos G. Sgourakis
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Article
| Open AccessA minority of final stacks yields superior amplitude in single-particle cryo-EM
Here the authors develop an iterative particle sieving method called CryoSieve, demonstrating this method outperforms other cryo-EM particle sorting algorithms to reveal that most particles are unnecessary in final stacks.
- Jianying Zhu
- , Qi Zhang
- & Chenglong Bao
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Article
| Open AccessGeometric constraint-triggered collagen expression mediates bacterial-host adhesion
Cells in the body live in geometrically constrained microenvironments. Here, Feng at al report that these constraints induce collagen IV expression which is responsible for location dependent bacterial adhesion.
- Yuting Feng
- , Shuyi Wang
- & Jianyong Huang
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Article
| Open AccessThe separation pin distinguishes the pro– and anti–recombinogenic functions of Saccharomyces cerevisiae Srs2
Here the authors report that the main role of the protein Srs2 in homologous recombination is to remove Rad51 from single stranded DNA, rather than to drive synthesis-dependent strand annealing.
- Aviv Meir
- , Vivek B. Raina
- & Eric C. Greene
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| Open AccessStructural and thermodynamic insights into antibody light chain tetramer formation through 3D domain swapping
Atomic-level structural examinations of antibody light chain aggregates are sparse. Here, the authors find an antibody light chain that maintains an equilibrium between monomeric and tetrameric states and show with its 3D structure that it engages in 3D domain swapping within its variable region.
- Takahiro Sakai
- , Tsuyoshi Mashima
- & Shun Hirota
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Article
| Open AccessPhospholipids are imported into mitochondria by VDAC, a dimeric beta barrel scramblase
Mitochondria depend on phospholipids supplied by the endoplasmic reticulum. Here, using biochemical assays and molecular dynamics simulations, authors identify VDAC as a scramblase-type lipid transporter that catalyze lipid entry.
- Helene Jahn
- , Ladislav Bartoš
- & Anant K. Menon
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Article
| Open AccessEnvironmental modulation of global epistasis in a drug resistance fitness landscape
Global epistasis can be used to reconstruct fitness landscapes and infer adaptive trajectories. Here, the authors investigate how environmental variation impacts patterns of global epistasis, finding that global epistasis in the malaria parasite P. falciparum can be modulated by drug concentration in the environment.
- Juan Diaz-Colunga
- , Alvaro Sanchez
- & C. Brandon Ogbunugafor
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Article
| Open AccessMachine learning-based motion tracking reveals an inverse correlation between adhesivity and surface motility of the leptospirosis spirochete
A common approach to study bacterial motility is fluorescent labelling, but this can be hampered by protein expression instability and/or interference with bacterial physiology. Here, Abe et al. describe a machine learning-based method for motion tracking of spirochetes on cultured animal cells, which does not require labelling and might be applied to study motility of other bacterial species.
- Keigo Abe
- , Nobuo Koizumi
- & Shuichi Nakamura
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Article
| Open AccessTransmembrane coupling of liquid-like protein condensates
Using a freestanding planar lipid membrane system, the authors show that liquid-like protein condensates on one side of a lipid membrane colocalize with those on the opposite side, suggesting a mechanism of information transfer across biological membranes.
- Yohan Lee
- , Sujin Park
- & Jeanne C. Stachowiak
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Article
| Open AccessTargeted mutagenesis of the herpesvirus fusogen central helix captures transition states
The early stages of viral fusogen conformational change required for enveloped viruses to infect cells is unclear. Here, authors capture the herpesvirus fusogen, glycoprotein B, in early transitional states by cryo-EM.
- Momei Zhou
- , Benjamin Vollmer
- & Stefan L. Oliver
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Article
| Open AccessA multi-reservoir extruder for time-resolved serial protein crystallography and compound screening at X-ray free-electron lasers
Protein serial crystallography at X-ray free-electron lasers (XFELs) is a powerful technique for structure determination. Here, authors present a device for sample delivery designed to abate challenges to non-specialists allowing for compound screening.
- Maximilian Wranik
- , Michal W. Kepa
- & Jörg Standfuss
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Article
| Open AccessCytosolic actin isoforms form networks with different rheological properties that indicate specific biological function
β-actin and γ-actin are nearly identical, and yet incorporate into different cytoskeletal structures. Here, the authors create isoform-pure reconstituted networks and study their structural and mechanical differences, underscoring the significance of the isoforms in diverse cellular functions.
- Peter Nietmann
- , Kevin Kaub
- & Andreas Janshoff
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Article
| Open AccessAssembly mechanism of the inflammasome sensor AIM2 revealed by single molecule analysis
Mechanistic insight into inflammasome formation is important for designing anti-inflammatory interventions. Here, the authors reveal the kinetics and distinct assembly modes of the early stages of the AIM2 inflammasome that detects pathogenic DNA.
- Meenakshi Sharma
- & Eva de Alba
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Article
| Open AccessStructural basis of a redox-dependent conformational switch that regulates the stress kinase p38α
p38α is a kinase that regulates many cellular processes. Here authors report that redox fluctuations induce conformational changes to fine-tune the p38α activity beyond its activation loop phosphorylation.
- Joan Pous
- , Blazej Baginski
- & Maria J. Macias
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Article
| Open AccessStructural basis of antibody inhibition and chemokine activation of the human CC chemokine receptor 8
CCR8 is a promising target in cancer immunotherapy. Here, authors generated mAb1, an antagonist antibody against CCR8 and determined structures of CCR8 in complex with mAb1 or the agonist CCL1, providing insights into CCR8 inhibition and activation.
- Dawei Sun
- , Yonglian Sun
- & Matthieu Masureel
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Article
| Open AccessA dynamic partitioning mechanism polarizes membrane protein distribution
Different membrane proteins dynamically polarize to organize signal transduction, but the underlying mechanism is unclear. Here, the authors show that a differential diffusion mediated partitioning process is sufficient to drive such spatiotemporal patterning of membrane-associated signaling proteins.
- Tatsat Banerjee
- , Satomi Matsuoka
- & Pablo A. Iglesias
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Article
| Open AccessLabel-free identification of protein aggregates using deep learning
The authors use deep learning to detect and segment unlabeled and unaltered protein aggregates in living cells from transmitted-light images. The method provides a way to quantitatively study protein aggregation dynamics in a simple, fast and accurate way.
- Khalid A. Ibrahim
- , Kristin S. Grußmayer
- & Aleksandra Radenovic
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Article
| Open AccessLipIDens: simulation assisted interpretation of lipid densities in cryo-EM structures of membrane proteins
Interpretation of lipid-like densities in cryo-EM structures of membrane proteins is challenging. Here authors present LipIDens, enabling molecular dynamics analysis of protein-lipid interactions.
- T. Bertie Ansell
- , Wanling Song
- & Mark S. P. Sansom
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Article
| Open AccessSynaptotagmin-7 outperforms synaptotagmin-1 to promote the formation of large, stable fusion pores via robust membrane penetration
Synaptotagmin-1 and -7 are calcium sensors that distinctly drive vesicular exocytosis. Here, using wild-type proteins but manipulating the composition of the target membranes, the authors show that synaptotagmin-7 is unusually robust at penetrating membranes.
- Kevin C. Courtney
- , Taraknath Mandal
- & Edwin R. Chapman
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Article
| Open AccessStochastic chain termination in bacterial pilus assembly
Adhesive type-1 pili from Escherichia coli are filamentous protein complexes consisting of a short tip and a long rod formed by up to several thousand copies of a major subunit. Here, Giese et al. reconstitute the entire type-1 pilus rod assembly reaction in vitro, using all constituent protein subunits, and identify a subunit that acts as an irreversible assembly terminator.
- Christoph Giese
- , Chasper Puorger
- & Rudi Glockshuber
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Article
| Open AccessDynamical control enables the formation of demixed biomolecular condensates
In this work, the authors report that protein-RNA condensates with shared proteins and distinct RNAs can form and persist in vitro and in cells as distinct entities if the nonshared RNA molecules are dynamically arrested, but the shared protein components are dynamically exchangeable.
- Andrew Z. Lin
- , Kiersten M. Ruff
- & Rohit V. Pappu
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Article
| Open AccessThe heat shock protein LarA activates the Lon protease in response to proteotoxic stress
The Lon protease is an important protein degradation machine and is conserved across the three domains of life. Here, the authors describe a small proteotoxic stress-induced protein that functions as an allosteric activator of Lon.
- Deike J. Omnus
- , Matthias J. Fink
- & Kristina Jonas
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Article
| Open AccessAcoustofluidic Interfaces for the Mechanobiological Secretome of MSCs
Efficient production of MSC secretome for therapeutic applications remains a challenging task. Here, the authors present an approach whereby an acoustofluidic mechanobiological environment can form reproducible 3D MSC aggregates, allowing for secretome production with high efficiency.
- Ye He
- , Shujie Yang
- & Tony Jun Huang
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Article
| Open AccessQuantification of ligand and mutation-induced bias in EGFR phosphorylation in direct response to ligand binding
The authors show that the oncogenic L834R EGFR mutation induces bias in EGFR signal transduction across the plasma membrane. While EGFR signalling is biased toward Y1068 phosphorylation, the mutation switches the preference to Y1173 phosphorylation.
- Daniel Wirth
- , Ece Özdemir
- & Kalina Hristova