Cryo-EM reconstruction of helical polymers: Beyond the simple cases DOI
Mark A. B. Kreutzberger, Ravi R. Sonani, Edward H. Egelman

et al.

Quarterly Reviews of Biophysics, Journal Year: 2024, Volume and Issue: 57

Published: Jan. 1, 2024

Helices are one of the most frequently encountered symmetries in biological assemblies. Helical symmetry has been exploited electron microscopic studies as a limited number filament images, principle, can provide all information needed to do three-dimensional reconstruction polymer. Over past 25 years, reconstructions helical polymers from cryo-EM images have shifted completely Fourier-Bessel methods single-particle approaches. The approaches allowed people surmount problem that very few crystalline order, and despite flexibility heterogeneity present these polymers, reaching resolution where accurate atomic models be built now become standard. While determining correct may simple for something like F-actin, many other particularly those formed small peptides, it much more challenging. This review discusses why determination problematic, trial-and-error still best approach. Studies macromolecular assemblies, such icosahedral capsids, usually found not imposing leads great reduction while at same time revealing possibly interesting asymmetric features. We show certain assemblies sometimes lead greatly improved resolution. Further, case supercoiled flagellar filaments bacteria archaea, we imposition only wrong, but is necessary, obscures mechanisms whereby supercoil.

Language: Английский

Afadin mediates cadherin-catenin complex clustering on F-actin linked to cooperative binding and filament curvature DOI Creative Commons
Rui Gong, Matthew J. Reynolds, Xiaoyu Sun

et al.

Science Advances, Journal Year: 2025, Volume and Issue: 11(7)

Published: Feb. 14, 2025

The E-cadherin–β-catenin–αE-catenin (cadherin-catenin) complex couples the cytoskeletons of neighboring cells at adherens junctions (AJs) to mediate force transmission across epithelia. Mechanical and auxiliary binding partners converge stabilize cadherin-catenin complex’s inherently weak actin filaments (F-actin) through unclear mechanisms. Here, we show that afadin’s coiled-coil (CC) domain vinculin synergistically enhance F-actin engagement. cryo–electron microscopy (cryo-EM) structure an E-cadherin–β-catenin–αE-catenin–vinculin–afadin-CC supra-complex bound reveals afadin-CC bridges adjacent αE-catenin actin-binding domains along filament, stabilizing flexible segments implicated in mechanical regulation. These cooperative contacts promote formation clusters F-actin. Additionally, cryo-EM variability analysis links individual strands nanoscale filament curvature, a deformation mode associated with cytoskeletal forces. Collectively, this work elucidates mechanistic framework by which afadin tune complex–cytoskeleton coupling support AJ function varying regimes.

Language: Английский

Citations

0
Cytoskeletal repair: Zyxin relieves actin stress from the inside out DOI
Patrick W. Oakes

Current Biology, Journal Year: 2025, Volume and Issue: 35(4), P. R148 - R150

Published: Feb. 1, 2025

Language: Английский

Citations

0
Afadin mediates cadherin-catenin complex clustering on F-actin linked to cooperative binding and filament curvature DOI Creative Commons
Rui Gong, Matthew J. Reynolds, Xiaoyu Sun

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 11, 2024

The E-cadherin-β-catenin-αE-catenin (cadherin-catenin) complex couples the cytoskeletons of neighboring cells at adherens junctions (AJs) to mediate force transmission across epithelia. Mechanical and auxiliary binding partners converge stabilize cadherin-catenin complex's inherently weak actin filaments (F-actin) through unclear mechanisms. Here we show that afadin's coiled-coil (CC) domain vinculin synergistically enhance F-actin engagement. cryo-EM structure an E-cadherin-β-catenin-αE-catenin-vinculin-afadin-CC supra-complex bound reveals afadin-CC bridges adjacent αE-catenin actin-binding domains along filament, stabilizing flexible segments implicated in mechanical regulation. These cooperative contacts promote formation clusters F-actin. Additionally, variability analysis links individual strands nanoscale filament curvature, a deformation mode associated with cytoskeletal forces. Collectively, this work elucidates mechanistic framework by which afadin tune complex-cytoskeleton coupling support AJ function varying regimes.

Language: Английский

Citations

2
Cryo-EM reconstruction of helical polymers: Beyond the simple cases DOI
Mark A. B. Kreutzberger, Ravi R. Sonani, Edward H. Egelman

et al.

Quarterly Reviews of Biophysics, Journal Year: 2024, Volume and Issue: 57

Published: Jan. 1, 2024

Helices are one of the most frequently encountered symmetries in biological assemblies. Helical symmetry has been exploited electron microscopic studies as a limited number filament images, principle, can provide all information needed to do three-dimensional reconstruction polymer. Over past 25 years, reconstructions helical polymers from cryo-EM images have shifted completely Fourier-Bessel methods single-particle approaches. The approaches allowed people surmount problem that very few crystalline order, and despite flexibility heterogeneity present these polymers, reaching resolution where accurate atomic models be built now become standard. While determining correct may simple for something like F-actin, many other particularly those formed small peptides, it much more challenging. This review discusses why determination problematic, trial-and-error still best approach. Studies macromolecular assemblies, such icosahedral capsids, usually found not imposing leads great reduction while at same time revealing possibly interesting asymmetric features. We show certain assemblies sometimes lead greatly improved resolution. Further, case supercoiled flagellar filaments bacteria archaea, we imposition only wrong, but is necessary, obscures mechanisms whereby supercoil.

Language: Английский

Citations

0