Description:

CELL & DEVELOPMENTAL BIOLOGY DEPARTMENT FACULTY CANDIDATE SEMINAR:

"Self-organization and load adaptation by mammalian endocytic actin networks"

Matthew Akamatsu, PhD

Postdoctoral Fellow

Drubin/Barne’s Lab, Department of Molecular and Cellular Biology

University of California, Berkeley

Join Us

Thursday, December 3, 2020

2:00 – 3:00 PM

Zoom Link:  https://northwestern.zoom.us/j/95641869681?pwd=SWE1TWtSQ0JRM1Z2NTdudmVERVlBdz09

Meeting ID: 956 4186 9681

Password: 861576

Dial-in: +1 312 626 6799

Abstract

Force generation by actin assembly shapes cellular membranes. The mechanisms that govern the organization of cytoskeletal complexes to produce directional force in cells are not understood. An experimentally constrained multiscale model shows that a minimal branched actin network is sufficient to internalize endocytic pits against membrane tension. Around 200 activated Arp2/3 complexes are required for robust internalization. A newly developed molecule-counting method determined that ~200 Arp2/3 complexes assemble at sites of clathrin-mediated endocytosis in human cells. Simulations predict that actin self-organizes into a radial branched array with growing ends oriented toward the base of the pit. Long actin filaments bend between attachment sites in the coat and the base of the pit. Elastic energy stored in bent filaments, whose presence was confirmed by cryo-electron tomography, contributes to endocytic internalization. Elevated membrane tension directs more growing filaments toward the base of the pit, increasing actin nucleation and bending for increased force production. Thus, spatially constrained actin filament assembly utilizes an adaptive mechanism enabling endocytosis under varying physical constraints.

Related Publication:

Akamatsu, M., Vasan, R., Serwas, D., Ferrin, M.A., Rangamani, P., Drubin, D.G. 2020. Principles of self-organization and load adaptation by the actin cytoskeleton during clathrin-mediated endocytosis. eLife. 9 e49840.  

Host: CDB Faculty Search Committee

 
 
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