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PhD Transfer Seminar – Rebecca Tam (Harris Lab)

December 1, 2020 @ 3:00 pm - 4:00 pm

Mechanisms of localized actin network assembly during actin cap formation in the Drosophila embryo


Cells undergo shape change to facilitate biological processes. The cytoskeleton cortex is a dynamic network of proteins that allow cells to change shape. Actin polymers are a major component of this cortical network. During early Drosophila melanogaster embryogenesis, an actin cap forms above the nucleus, and the growth of this structure creates a dome that houses the mitotic apparatus. The centrosomes and specific actin regulators encourage actin cap formation and growth. My experiments show that centrosomes have a closer relationship with actin regulators like Rac-GEF Sponge and Rac-GTP during the initial stages of cap formation. Specifically, these upstream regulators of the Arp2/3 nucleation complex localize to deep plasma membrane folds that emanate towards the centrosomes. My project will test a hypothesis that microtubule-based forces pull the plasma membrane towards centrosomes for localized accumulation and activity of the Arp2/3 induction pathway. Additionally, I will test the roles of dynein, Aurora A, and PIP3. This structural change may locally activate signalling pathways to promote actin network assembly. Furthermore, I will study how Dia-based actin bundles act in conjunction with the Arp2/3 induction pathway and the induced Arp2/3 networks to encourage the growth of the cap. My studies combine live imaging approaches with genetic perturbations. This research will characterize a signal transduction mechanism that induces cortical actin network assembly and cell shape change.

Join Zoom Meeting:

Tuesday, December 1st, 2020 at 3:00pm


Meeting ID: 848 1003 1055

Host: Tony Harris (tony.harris@utoronto.ca)


December 1, 2020
3:00 pm - 4:00 pm