QBI Neuroscience Seminar: 'Vital role of the tropomyosin decorated actin filaments in the the structure and function of the axon initial segment'

Event Details

Date:

Monday, 26 November 2018 - Monday, 26 November 2018

Time:

11:00 am - 12:00 pm

Room:

QBI Level 7 Auditorium

UQ Location:

Queensland Brain Institute (St Lucia)

URL:

http://www.qbi.uq.edu.au/neuroscience-seminars

Event category(s):

Full Description:: Adjunct Professor Pirta Hotulainen
University of Helsinki, Finland

Title: 'Vital role of the tropomyosin decorated actin filaments in the structure and function of the axon initial segment'

Abstract:

The axon initial segment (AIS) is the site of action potential initiation and serves as a diffusion barrier that helps maintain neuronal polarity. The specific role of actin in the AIS, however, has remained unclear. In my talk, I will discuss our recent results on the properties and regulation of the AIS actin cytoskeleton. Using STORM and SIM super-resolution techniques, we found a population of relatively stable actin filaments decorated by tropomyosin isoform Tpm3.1 in the AIS. These filaments are part of the periodic sub-membranous actin rings and AIS actin patches. Genetic depletion of Tpm3.1 led to the reduced accumulation of AIS markers. Inhibition of Tpm3.1 in cultured hippocampal neurons led to the loss of AIS structure, the AIS diffusion barrier, and the clustering of sodium ion channels. These results suggest that the tropomyosin decorated actin filaments play a fundamental role in the maintenance of the structure and function of the AIS.