QBI Seminar: Role of myosin VI in neuroexocytosis
Event Details
- Date:
- Thursday, 14 August 2014
- Time:
- 9:00 am - 10:00 am
- Room:
- Auditorium, Level 7
- UQ Location:
- Queensland Brain Institute (St Lucia)
- URL:
- http://www.qbi.uq.edu.au/neuroscience-seminars
- Event category(s):
Event Contact
- Name:
- Mr Reeza Nazer
- Phone:
- 66353
- Email:
- r.nazer@uq.edu.au
- Org. Unit:
- Queensland Brain Institute
Event Description
- Full Description:
- Speaker:
Dr Vanesa Tomatis
Queensland Brain Institute, The University of Queensland
Title:
Role of myosin VI in neuroexocytosis
Abstract:
Neuroendocrine secretory granules (SGs) are storage compartments for neuropeptides and hormones that are released in response to stimulation. Prior to fusion with the plasma membrane SGs are recruited and mobilised through the F-actin cortical network localised underneath the plasma membrane. However, the mechanism underpinning these events is still unclear. We hypothesised that cytosolic proteins are recruited onto SGs in a Ca2+-dependent manner, facilitating their interaction with the cortical actin and subsequent transport towards fusion sites. By combining mass spectrometry with biochemistry and microscopy approaches, we identified myosin VI as a protein that interacts with SGs in a Ca2+-dependent manner and demonstrated that myosin VI function is required to maintain evoked exocytosis during long periods of stimulation. Myosin VI small insert and no insert isoforms are expressed in PC12 cells, however we have shown that only myosin VI small insert specifically plays a major role in regulated exocytosis by regulating the tethering of SGs to the cortical actin network, a crucial step for their fusion. Furthermore, we identified a new c-Src-phosphorylation motif, which is only present in myosin VI small insert, and show that it is indeed phosphorylated by c-Src kinase. Using a c-Src kinase inhibitor together with a mutagenesis approach, we proved that phosphorylation of this motif is essential for the role of myosin VI small insert during SG exocytosis.Myosin VI is targeted to different subcellular compartments through the interaction with various adaptor proteins in order to fulfil its function. In view of the novel role we have identified for myosin VI in neuroexocytosis, it is likely that other, currently unknown, adaptor proteins mediate its recruitment to SGs. Preliminary data describing a novel myosin VI binding partner, Mena, and its role in targeting myosin VI to SGs, will be discussed.
Directions to UQ
- Google Map:
-
- Directions:
- St Lucia Campus | Gatton campus.
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