Position
Lecturer in Neuroscience
Head, Laboratory of Molecular Neuroscience
(Brain & Mind Research Institute)
Qualifications
BSc (Hons) Tor, MSc McMaster, PhD Melb
Dr. Holsinger lectures in the Faculties undergraduate and postgraduate Neuroscience
programs. His lectures cover communication in the nervous system, neurophysiololgy, pathophysiology and neuronal plasticity.
Research Interest
Dr. Holsingers’ research interests currently focus on Alzheimer’s disease (AD), specifically, the enzyme that initiates formation of Aβ amyloid plaques. Aβ amyloid deposition is the pathognomonic feature of AD and cytotoxic Aβ oligomers are considered to be responsible for neuronal degeneration. Aβ is proteolytically derived from the type 1 amyloid precursor protein (APP) by the sequential action of β- and γ-secretases. Since β-secretase (BACE1) initiates Aβ amyloid biogenesis, much emphasis has been placed on this enzyme as a probable target for therapeutic intervention.
Research Students
- Munther Alomari MSc student
- Ibrahim Al-Omat PhD student
- Jing Xiao MSc student
- Ben Nguyen Honours student
- Melissa Rea Honours student
- Ibrahim Al-Salti Honours student - Pharmacy
- Zong-Yuan Zhao Honours student - Pharmacy
- Marietta Salim Research student
- Farjana Afroz Research Assistant
Key research areas
Physiological and pathophysiological regulation of BACE1
The physiological role of BACE1 is currently unknown. Using cellular and animal models of Alzheimer's disease we are investigating the regulation of BACE1 under physiological and pathophysiological conditions using stressors commonly associated with neurodegenerative diseases.
Biochemical characterization of BACE1 isoforms and derived products in human brain cortex
We have observed that BACE1 protein in human brain is expressed as a 70 kDa doublet. In addition to this species we have also identified high and low molecular weight antibody immunoreactive species. Our current focus is to further characterize these BACE1 isoforms as they may indicate heterogeneity due to different degrees of maturation, alternative posttranslational products, alternatively spliced forms, degradation products of BACE1, or complexes of BACE1 with partner proteins.
Identifying BACE1 interacting proteins
To-date, more than fifteen proteins have been shown to interact with BACE1. Many of these proteins have been shown to be substrates of the enzyme while others have been associated with the C-terminal region of BACE1. Interestingly, none of the studies published have reported duplication of results indicating that other interacting proteins and/or substrates may exist. In our pursuit of identifying proteins that may interact with BACE1, and thereby stabilize the protein in AD brain, we have recently identified novel proteins that interact with the enzyme and are currently in the process of validating our results.
Analysis of BACE1 splice variants and their contribution to enzyme activity
Alternative gene splicing is a key mechanism for expanding proteome diversity. In addition to playing crucial roles in cell function such as neuronal signalling and axon guidance, alternatively spliced forms of proteins have also been implicated in disease states. Three alternitively spliced variants of BACE1 have been identified in both neuronal and peripheral tissues. The aim of this project is to determine the activity of each of the splice variants in an attempt to decipher their contribution to the overall generation of Aβ. This information will be important when evaluating inhibitors of BACE1 as a therapeutic for AD.
Objectives
- Understand the physiological relevance of BACE1
- Understand the mechanism(s) leading to increased BACE1 in AD brain
- Identify novel BACE1 interacting proteins
Recent Achievements
- First to demonstrate that BACE1 protein and activity are increased in Alzheimer's disease brain
- Demonstrated that the increase in BACE1 protein levels in AD brain are a result of protein stabilization and/or deficient degradation
- Demonstrated that BACE1 activity is increased in AD cerebrospinal fluid
- Identified five novel BACE1-interacting proteins
Techniques
- Molecular Biology (in vitro and in vivo gene silencing, RT-PCR, cloning, site-directed mutagenesis)
- Protein Chemistry (western blotting, protein expression and purification)
- Cell Biology (tissue culture, cell transfections)
- Enzymology (time-resolved fluorescence, fluorogenic assays; zymography)
Dr Holsinger's recent publications are available from this site.
For more information:
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Last update: 1st February 2008
