Journal: Nat Commun / Year: 2024 Title: In situ structure of actin remodeling during glucose-stimulated insulin secretion using cryo-electron tomography. Authors: Weimin Li / Angdi Li / Bing Yu / Xiaoxiao Zhang / Xiaoyan Liu / Kate L White / Raymond C Stevens / Wolfgang Baumeister / Andrej Sali / Marion Jasnin / Liping Sun / Abstract: Actin mediates insulin secretion in pancreatic β-cells through remodeling. Hampered by limited resolution, previous studies have offered an ambiguous depiction as depolymerization and ...Actin mediates insulin secretion in pancreatic β-cells through remodeling. Hampered by limited resolution, previous studies have offered an ambiguous depiction as depolymerization and repolymerization. We report the in situ structure of actin remodeling in INS-1E β-cells during glucose-stimulated insulin secretion at nanoscale resolution. After remodeling, the actin filament network at the cell periphery exhibits three marked differences: 12% of actin filaments reorient quasi-orthogonally to the ventral membrane; the filament network mainly remains as cell-stabilizing bundles but partially reconfigures into a less compact arrangement; actin filaments anchored to the ventral membrane reorganize from a "netlike" to a "blooming" architecture. Furthermore, the density of actin filaments and microtubules around insulin secretory granules decreases, while actin filaments and microtubules become more densely packed. The actin filament network after remodeling potentially precedes the transport and release of insulin secretory granules. These findings advance our understanding of actin remodeling and its role in glucose-stimulated insulin secretion.
A: 12402.688 Å / B: 12402.688 Å / C: 3100.672 Å α=β=γ: 90.0 °
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Supplemental data
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Sample components
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Entire : INS-1E
Entire
Name: INS-1E
Components
Cell: INS-1E
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Supramolecule #1: INS-1E
Supramolecule
Name: INS-1E / type: cell / ID: 1 / Parent: 0
Source (natural)
Organism: Rattus (rat)
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Experimental details
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Structure determination
Method
cryo EM
Processing
electron tomography
Aggregation state
cell
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Sample preparation
Buffer
pH: 7.45
Vitrification
Cryogen name: ETHANE
Sectioning
Focused ion beam - Instrument: OTHER / Focused ion beam - Ion: OTHER / Focused ion beam - Voltage: 30 / Focused ion beam - Current: 0.5 / Focused ion beam - Duration: 30 / Focused ion beam - Temperature: 78 K / Focused ion beam - Initial thickness: 1000 / Focused ion beam - Final thickness: 230 Focused ion beam - Details: The value given for _em_focused_ion_beam.instrument is FEI Aquilos2. This is not in a list of allowed values {'DB235', 'OTHER'} so OTHER is written into the XML file.
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Electron microscopy
Microscope
FEI TITAN
Image recording
Film or detector model: FEI FALCON IV (4k x 4k) / Average electron dose: 2.0 e/Å2
Electron beam
Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
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