Cappai Laboratory
| Contact: | Roberto Cappai |
|---|---|
| Phone: | +61 3 8344 2556 |
| Fax: | +61 3 9347 6750 |
| Email: | r.cappai@unimelb.edu.au |
The Cappai laboratory studies the molecular, cellular and structural interactions that result in Alzheimer's disease, prion disease and Parkinson's disease. The group has expertise in a diversity of molecular, biophysical and cell biology techniques, thus allowing different approaches to be applied to a given problem. The laborartory is located in the Bio21 Institute, 30 Flemington Rd, Parkville. www.bio21.org
Key research areas are:
Alzheimer's disease (AD)
The key pathological hallmarks of AD are the extracellular amyloid plaques and the intracellular tangles. The principle component of plaques is the amyloid beta peptide (Aβ). The Aβ peptide is derived from the proteolytic cleavage of the amyloid precursor protein (APP). The Aβ peptide is believed to provide the neurotoxic insult that causes the neurodegeneration that leads to AD.
Functional studies of the APP-family.
The normal function of APP and the amyloid precursor-like proteins (APLP1 and APLP2) is unknown. The current data suggests they have a role in modulating cellular viability, since reducing the redundancy of the APP-gene family in APP-family double and triple knockout mice can lead to a lethal phenotype. Current studies are using APP-family knockout mice for in vitro cell based assays and in vivo whole animal studies to determine how APP-family expression affects cellular function. A major effort involves studying the N-terminal Cu-binding domain (CuBD) which has a role in modulating Cu homeostasis and Cu-mediated toxicity. A molecular target for the APP:Cu complex is the proteoglycan molecule called glypican-1. These studies will provide a clearer insight into the normal function of APP.
Mechanisms of amyloid toxicity.
The cellular and molecular factors mediating Aβ neurotoxicity remain poorly defined. Cell culture models are being used to identify the cellular and subcellular changes that occur following exposure to toxic Aβ. The proteins and cellular factors that modulate Aβ toxicity are being investigated. These studies will identify the neurotoxic Aβ species, markers for Aβ toxicity and targets that can be inhibited to prevent neurotoxicity.
Structural biology of the amyloid precursor protein (APP).
The aim of this project is to understand the three dimensional structure of the APP molecule either alone or in co-complex with APP-binding proteins. Knowing the structure of APP will provide insights into APP function and the structures will also identify targets upon which to develop drugs to modulate APP processing and therefore prevent Aβ generation.
Parkinson's disease (PD)
PD is a movement disorder caused by the loss of neurons from the substantia nigra. The key pathological hallmark of PD is the intracellular inclusions called Lewy bodies which are composed mainly of the α-synuclein protein. In addition to α-synuclein a number of other genes have been identified using genetic studies to directly cause PD in either an autosomal dominant or recessive manner.
Structural properties of α-synuclein.
The α-synuclein protein is a cytoplasmic protein that undergoes a structural transition from an unfolded state into an α-helical containing conformation. We have been studying the factors that modulate this structural change and shown that dopamine and membranes can alter the biophysical properties of α-synuclein. Our goal is to relate these in vitro studies to cell based assays and in vivo models of PD.
Prion disease
The prion diseases which include Creutzfeldt-Jakob Disease (CJD) and mad cow disease are a group of transmissible neurodegenerative diseases. The infectious agent is believed to be composed solely of a protein called the prion protein and devoid of nucleic acid.
The structural and biophysical properties of the prion molecule.
Our work uses a synthetic peptide of the PrP molecule corresponding to residues 106-126 as a model for neurotoxic PrP to study the cellular and subcellular factors responsible for PrP106-126 toxicity and to correlate this to its biophysical properties. We have shown that he hydrophobic domain, and its ability to bind metals, modulate neurotoxic activity. We are seeking to extend these studies into the full-length forms of PrP and its behaviour in cell culture
Objectives
- To develop therapeutics by identifying the key molecular interactions and cellular pathways that are critical for neurotoxicity.
- Determining the normal function of the proteins involved in AD, PD and prion disease.
- Solving the structures of the proteins involved in AD, PD and prion disease.
Major Achievements
- Identifying APP as a modulator of metal homeostasis.
- Identifying dopamine as a modulator of α-synuclein aggregation
- Identifying glypican-1 as a target for the APP:Cu complex.
- Solving the structure of the N-terminal growth factor and copper binding domains of APP.
- Identifying metals as modulators of PrP106-126 aggregation and neurotoxicity.
Techniques
- Molecular biology
- Cell biology
- Protein expression and purification
- Structural biology
- Neurochemistry
Collaborations
Departmental:
Drs Kevin Barnham, Ashley Bush, Robert Cherny, Steven Collins, Janetta Culvenor, Cyril Curtain, Genevieve Evin, Qiao-Xin Li, Colin Masters, Victor Villemagne and Tony White
University:
Assoc Prof James Camakaris (Genetics), Dr Andrew Hill (Biochemistry)
External:
International Collaborators
- Prof Gerd Multhaup, Free University, Berlin, Germany
- Prof Lars-Åke Fransson, Dr Katrin Mani, Lund University, Lund, Sweden
- Prof Thomas Willnow, Dr Olav Andersen, Max-Delbrück Center, Berlin, Germany
- Prof Maheswari, University of Madras, Chennai, India
Funding
- NHMRC Program Grant
- NHMRC Senior Research Fellowship
- ARC Discovery Grant
Recent Publications
- Aves da costa C., Dunys J., Wilk S., Cappai R. and Checler F., 6-hydroxy-dopamine but not 1-methyl-4-phenylpyridinium abolishes α-synuclein anti-apoptotic phenotype by inhibiting its proteasomal degradation and by promoting its aggregation. Journal of Biological Chemistry (2006) 281: 9824-9831
- Andersen O.M., Reiche J., Schmidt V., Gotthardt M., Spoelgen R., Behlke J., von Arnim A.F., Breiderhoff T., Jansen P., Wu X., Bales K.R., Cappai R., Masters C.L., Gliemann J., Mufson E.J., Hyman B.T., Paul S.M., Nykjær A. and Willnow T.E. SorLa/LR11, a neuronal sorting receptor that regulates processing of the amyloid precursor protein. Proceeding of the National Academy of Sciences (USA) (2005) 102: 13461-13466
- Cappai R., Leck S-L., Tew D.J., Williamson N.A., Smith D.P., Galatis D., Sharples R.A., Curtain C.C., Ali F., Cherny R.A., Culvenor J.G., Bottomley S.P., Masters C.L., Barnham K.J. and Hill A.F. Dopamine promotes α-synuclein aggregation into SDS-resistant soluble oligomers via a distinct folding pathway. FASEB Journal (2005) 19: 1377-1379
- Cappai R., Cheng F., Ciccotosto G.D., Needham B.E., Masters C.L., Multhaup G., Fransson L-A and Mani K. The Amyloid Precursor Protein (APP) of Alzheimer disease and its paralog APLP2 modulate the Cu/Zn-NO catalyzed degradation of glypican-1 heparan sulfate in vivo. Journal of Biological Chemistry (2005) 280: 13913-13920
- Barnham K.J, McKinstry W.J., Multhaup G., Galatis D., Morton C.J., Curtain C.C., Williamson N.A., White A.R., Hinds M.G., Norton R.S., Beyreuther K., Masters C.L., Parker M.W. and Cappai R. Structure of the Alzheimer's disease amyloid precursor protein copper binding domain: a regulator of neuronal copper homeostasis. Journal of Biological Chemistry (2003) 278:17401-17407
- Barnham K.J, Ciccotosto G.D., Tickler A.K., Ali F.E., Smith D.G., Williamson N.A., Lam Y-H., Carrington D., Tew D., Kocak G., Volitakis I., Separovic F., Barrow C.J., Wade J.D., Masters C.L., Cherny R.A., Curtain C.C., Bush A.I. and Cappai R. Neurotoxic, redox-competent Alzheimer's β-amyloid is released from lipid membrane by methionine oxidation. Journal of Biological Chemistry (2003) 278: 42959-42965.
- White A.R., Multhaup G., Galatis, D., McKinstry W.J., Parker M.W., Pipkorn R., Beyreuther K., Masters C.L. and Cappai R., Contrasting, species-dependent modulation of copper-mediated neurotoxicity by the Alzheimer's disease amyloid precursor protein. Journal of Neuroscience (2002) 22:365-376
- Jobling M.F., Huang X., Stewart L.R., Barnham K.J., Curtain C., Volitakis I., Perugini M., White A.R., Cherny R., Masters C.L., Barrow C.J., Collins S.J., Bush A.I., and Cappai R. Copper and zinc binding modulates the aggregation and neurotoxic properties of the prion peptide PrP106-126. Biochemistry (2001) 40, 8073-8084