QBI Seminar: 'Shape-shifting Dynamin: Multiple dynamin conformations for endocytosis and more'
Event Details
- Date:
- Wednesday, 16 September 2015 - Wednesday, 16 September 2015
- Time:
- 12:00 pm - 1:00 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):
Event Contact
- Name:
- Ms Deirdre Wilson
- Phone:
- 66300
- Email:
- d.wilson5@uq.edu.au
- Org. Unit:
- Queensland Brain Institute
Event Description
- Full Description:
- Professor Phillip J Robinson
\NHMRC Senior Principal Research Fellow and Head, Cell Signalling Unit, Children’s Medical Research Institute, The University of Sydney, Australia
Title: Shape-shifting Dynamin: Multiple dynamin conformations for endocytosis and more
Abstract:
The classical dynamins, dynI, II and III, are characterised by their ability to oligomerise to large assemblies with elevated GTPase activity. They mediate clathrin-mediated endocytosis (CME) and have CME-independent roles in fusion pore expansion and cytokinesis. They share a common G domain, bundle signal element (BSE) and middle domain (MiD). The maximum GTPase activity is stimulated through a concerted structural rearrangement that brings pairs of G domains face-to-face. They have two signalling input domains: the proline rich domain (PRD) binds different SH3 domain proteins at different sites and stimulates ring oligomerisation and mid-level activity; while their pleckstrin homology domains (PHDs) detect specific vesicle neck lipids to stimulate helical assembly and high-activity for fission. Oligomerisation is thought to account for activity stimulation, yet it is unclear how the enzyme distinguishes multiple oligomerisation signals.
This presentation will show unpublished studies revealing how dynamin is regulated by differential signal inputs via the PRD or the PHD to produce structurally distinct oligomerised assembly states, via the MiD. Within the 4-helix bundle of the MiD dynI and II have an alternatively spliced α2 helix, producing a or b versions of each. We show that this helix mediates assembly of a variety of dynamin oligomers with different activity states. These studies reveal the existence of multiple dynamin oligomerisation conformations within rings or helices. We also report on a specific allosteric signalling pathway within dynamin, which suggests a mechanism whereby the energy from GTP hydrolysis at the G domain may be transmitted through the MiD to mediate membrane fission by the PH domain.
Directions to UQ
- Google Map:
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- Directions:
- St Lucia Campus | Gatton campus.
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