Adjunct Professor Pirta Hotulainen

University of Helsinki, Finland

Title: "Vital role of the tropomyosin decorated actin filaments in the 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. 



About Neuroscience Seminars

Neuroscience seminars at the QBI play a major role in the advancement of neuroscience in the Asia-Pacific region. The primary goal of these seminars is to promote excellence in neuroscience through the exchange of ideas, establishing new collaborations and augmenting partnerships already in place.

Seminars in the QBI Auditorium on Level 7 are held on Wednesdays at 12-1pm, which are sometimes simulcast on Zoom (with approval from the speaker). We also occassionally hold seminars from international speakers via Zoom. The days and times of these seminars will vary depending on the time zone of the speaker. Please see each seminar listed below for details. 


Neuroscience Seminars archive 2005-2018