November 1, 2018 at 9:00 pm

Math-Biology Seminar | Local, Biased Polymerization Mediates Slow Axonal Transport of Actin, Nov. 13

Nilaj Chakrabarty, portrait outdoors

Nilaj Chakrabarty

The Dynamical Systems and Mathematical Biology Seminar series presents Nilaj Chakrabarty discussing “Local, biased polymerization mediates the slow axonal transport of actin” on Tuesday, Nov. 13, from 3:05 to 4 p.m. in Morton 313.

Chakrabarty is a PhD. candidate in Physics and Astronomy.

Abstract: Classic pulse-chase studies have shown that actin is conveyed in slow axonal transport, but the mechanistic basis for this movement is unknown. Recent live-cell imaging has revealed that axonal actin was surprisingly dynamic, with focal assembly/disassembly events (“actin hotspots”) and elongating polymers along the axon (“actin trails”). Using a combination of live imaging, superresolution microscopy, and modeling, we have explored how these dynamic structures can lead to bulk transport of actin. We found relatively more actin trails elongated anterogradely as well as an overall slow, anterogradely biased flow of actin in axon shafts. Starting with first principles of monomer/filament assembly and incorporating imaging data, we generated a quantitative model simulating axonal hotspots and trails. Our simulations predict that the axonal actin dynamics indeed lead to a slow anterogradely biased flow of the population. Collectively, the data point to a surprising scenario where local assembly and biased polymerization generate the slow axonal transport of actin without involvement of microtubules (MTs) or MT-based motors.


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