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DTSTAMP:20260803T090304Z
UID:1786606200@ist.ac.at
DTSTART:20260813T093000
DTEND:20260813T103000
DESCRIPTION:Speaker: Manjunath Javoor\nhosted by Rafal Klajn\nAbstract: Cel
 l motility depends on the protrusive force generated by the actin cytoskel
 eton at the leading edge of cells. In lamellipodia\, thin protrusions at t
 he front of migrating cells\, actin forms higher-order networks with versa
 tile physical properties. Previous studies have hinted at the presence of 
 different sub-populations of filaments and their spatial organization with
 in actin filament networks at the leading edge of migrating cells. Due to 
 limitations of existing experimental methods\, it has not been possible to
  fully describe the complexity of the actin filament populations involved 
 in protrusions at the leading edge.Cryo-electron tomography (cryo-ET) has 
 been used to describe the actin networks in cellular protrusions at single
  filament resolution in 3D. However\, these descriptions have been limited
  to 1-2 μm2 area of the protrusions\, providing merely snapshots of much 
 larger assemblies that span serval tens to hundreds of square microns area
 . Consequently\, they have not provided a holistic overview of the existin
 g variability within actin networks. We therefore lack a comprehensive und
 erstanding of how actin network geometries orchestrate cell migration.To a
 ddress these challenges\, I developed a montage cryo-electron tomography w
 orkflow to obtain three-dimensional views of lamellipodial regions coverin
 g areas of up to 100 μm2 at single-filament resolution. Seamless three-di
 mensional tomogram stitching is achieved by combining neural-network-based
  denoising strategies with novel optical-flow-based algorithms\, thereby p
 reserving filament continuity across large reconstructed volumes. Our comp
 utational analysis pipeline enabled us to vectorize all filaments within t
 hese volumes\, including filaments reaching lengths of up to 4 μm. The da
 ta generated here represent a valuable resource for the actin community\, 
 as they provide one of the most detailed and extensive three-dimensional d
 escriptions of actin filament architecture in the lamellipodium. Specifica
 lly\, they reveal accurate F-actin concentrations\, filament length distri
 butions\, connectivity\, and the spatial organization of filament sub-popu
 lations. These datasets can be used to support and constrain biophysical a
 nd theoretical models of actin network organization\, dynamics\, and force
  generation.
LOCATION:Sunstone Bldg / Ground floor / Big Seminar Room B / 63 seats (I23.
 EG.102) and Zoom\, ISTA
ORGANIZER:
SUMMARY:Manjunath Javoor: Thesis Defense: Large-scale imaging of cellular a
 ctin networks at single-filament resolution using montage cryo-electron to
 mography
URL:https://talks-calendar.ista.ac.at/events/6576
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