ISSN 1443-0193 Australian Biochemist The Magazine of the Australian Society for Biochemistry and Molecular Biology Inc. Volume 47 AUGUST 2016 No.2 SHOWCASE ON RESEARCH Protein Misfolding and Proteostasis THIS ISSUE INCLUDES Showcase on Research Regular Departments A Short History of Amyloid SDS (Students) Page Molecular Chaperones: The Cutting Edge Guardians of the Proteome Off the Beaten Track When Proteostasis Goes Bad: Intellectual Property Protein Aggregation in the Cell Our Sustaining Members Extracellular Chaperones and Forthcoming Meetings Proteostasis Directory INSIDE ComBio2016 International Speaker Profiles Vol 47 No 2 August 2016 AUSTRALIAN BIOCHEMIST Page 1 ‘OSE’ Fill-in Puzzle We have another competition for the readers of the Australian Biochemist. All correct entries received by the Editor (email [email protected]) before 3 October 2016 will enter the draw to receive a gift voucher. With thanks to Rebecca Lew. The purpOSE is to choOSE from thOSE words listed and transpOSE them into the grid. So, clOSE your door, repOSE in a chair, and diagnOSE the answers – you don’t want to lOSE! 6 letters 8 letters ALDOSE FRUCTOSE FUCOSE FURANOSE HEXOSE PYRANOSE KETOSE RIBOSE 9 letters XYLOSE CELLULOSE GALACTOSE 7 letters RAFFINOSE AMYLOSE TREHALOSE GLUCOSE LACTOSE 11 letters MALTOSE DEOXYRIBOSE PENTOSE Australian Biochemist – Editor Chu Kong Liew, Editorial Officer Liana Friedman © 2016 Australian Society for Biochemistry and Molecular Biology Inc. All rights reserved. Page 2 AUSTRALIAN BIOCHEMIST Vol 47 No 2 August 2016 SHOWCASE ON RESEARCH EDITORIAL Molecular Origami: the Importance of Managing Protein Folding In my humble opinion, the most important biological transcription, RNA processing and transport, translation, molecule is the protein. After water, it is by far the most protein folding, protein transport and protein degradation abundant molecule in the human body, making up must be tightly regulated. Together these processes make approximately 20% of our body weight. This means that, up the proteostasis network. on average, a human of 75 kg contains around 15 kg of The proteostasis network regulates proteome protein, which translates to an astounding 1.5 x 1028 protein homeostasis by maintaining the delicate balance between molecules (on par with the estimated number of stars in the production and disposal of proteins. In our second the universe). This protein content is not a static entity, article, Dezerae Cox, Rebecca San Gil, Anthea Rote and it has been estimated that about 400 grams of protein is Heath Ecroyd describe the function of arguably the most synthesised and degraded each day in the human body. important contributors to the proteostasis network, the Making even a single protein is not an easy task; one chaperone proteins. Degradation of proteins by autophagy only has to look at any structure in the protein data or the ubiquitin-proteasome system (UPS) and active bank to appreciate the exquisite beauty and complexity compartmentalisation of misfolded proteins into specific of a natively folded protein structure. Importantly, the regions in the cell (eg. the aggresome) also contribute to biological function of proteins is most often critically proteome quality control. The careful regulation of these dependent on them reaching their folded state. Correct processes is critical for protection against the toxicity protein folding is not always achieved. Single point associated with mutant, misfolded and/or damaged mutations can destabilise, and thus prevent, proper folding proteins associated with human disease. In their of a protein and certain environmental conditions, such as contribution, Mona Radwan, Rebecca Wood, Xiaojing macromolecular crowding, inappropriate ionic strength, Sui and Danny Hatters consider protein aggregation in oxidative stress and extremes of pH and temperature are the cell and its role in the toxicity associated with this known to promote the formation of misfolded states. If left process. Last, while the vast majority of research into unchecked, misfolded proteins can aggregate into insoluble protein misfolding has centered on what happens inside protein deposits. Many disease states are associated with the cell, in our last article, Amy Wyatt explains why the abnormal protein deposits comprised of aggregated proteostasis network is also crucial outside the cell. protein, including an insoluble fibrillar aggregate known The study of protein misfolding is an exciting as amyloid. In our first article, one of the pioneers in this and dynamic field which has moved from original field, Margie Sunde, describes the early discoveries in observations of single proteins to that of the misfolding protein misfolding and the formation and structure of of large subsections of the proteome. Whilst this area amyloid associated with human disease, before outlining of research has obvious importance to age-related the intriguing world of functional amyloid. neurodegenerative diseases in which protein aggregates The term protein homeostasis or proteostasis refers are a hallmark of the disorders (eg. Parkinson’s disease), to the maintenance of the proteome in a conformation, there is emerging recognition of the importance of the concentration and in a location that is required for their maintenance of proteostasis in a range of conditions correct function. Given that a single cell has to handle including type 2 diabetes, cataract, pre-eclampsia and around 200 million protein molecules made from up to many forms of cancer. Indeed, given the astounding 20,000 protein encoding genes, it is an understatement number of protein molecules that need to be kept in check to say that proteostasis is important in the normal in the human body, it is remarkable that the proteostasis housekeeping of a cell. In order to produce a properly network manages to protect cells from diseases associated functioning (non-aggregating) proteome, the processes of with proteome stress at all. Justin Yerbury Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522 [email protected] Protein Misfolding and Proteostasis Cover Illustration Total internal reflection fluorescence Guest Editors: Justin Yerbury and Heath Ecroyd microscopy of amyloid fibrils 4 A Short History of Amyloid: from Abnormal Aggregation to formed from a-synuclein, imaged Functional Assembly using Thioflavin T (blue) and Nile Margie Sunde Red (green) staining. The small heat 8 Molecular Chaperones: Guardians of the Proteome shock protein Hsp27 (red) binds to Dezerae Cox, Rebecca San Gil, Anthea Rote and Heath Ecroyd these amyloid fibrils. 11 When Proteostasis Goes Bad: Protein Aggregation in the Cell Image courtesy of Mathew Horrocks, Mona Radwan, Rebecca Wood, Xiaojing Sui and Danny Hatters Dezerae Cox and Caitlin Johnston 14 Extracellular Chaperones and Proteostasis (Illawarra Health and Medical Research Amy Wyatt Institute, University of Wollongong). Vol 47 No 2 August 2016 AUSTRALIAN BIOCHEMIST Page 3 SHOWCASE ON RESEARCH A Short History of Amyloid: from Abnormal Aggregation to Functional Assembly Margie Sunde* Discipline of Pharmacology, School of Medical Sciences, University of Sydney, NSW 2006 *Corresponding author: [email protected] Amyloid fibrils are long protein fibrils, usually straight the way in diagnosis and treatment of systemic amyloid and unbranching (Fig. 1A), which have an underlying disease. At amyloid meetings, clinicians presented ordered β-sheet structure in which the β strands run at alongside basic scientists such as Jeff Kelly, Ron Wetzel, right angles to the fibril long axis. This structured core Dan Kirschner, Peter Lansbury and Paul Fraser, who gives rise to a cross-β X-ray fibre diffraction pattern, with were starting to apply biophysical methods to study dominant reflections at ~4.7 Å on the meridian and ~10 Å disease-associated variant proteins in order to understand on the equator of the pattern, and to diagnostic staining why proteins with a stable globular structure would self- with the dye Congo red (Fig. 1B). This simple description assemble into an insoluble, fibrillar form (3). Colin Blake, of amyloid structure and character has held even as our as a pioneer protein crystallographer, had solved the three understanding of the roles of amyloid fibrils in biology dimensional structures of both human lysozyme and and disease has changed dramatically in recent years. transthyretin and he was keen to understand why and Extracellular, fibrillar amyloid deposits associated with how variants of these two proteins formed amyloid fibrils human disease were first described by the pathologist and human disease. Louise Serpell was a DPhil student Virchow in 1854 (1). The observation of apple-green when I joined the laboratory and she initiated electron birefringence from Congo red-stained deposits in tissue microscopy studies of transthyretin fibrils isolated from sections was considered pathognomonic for amyloidosis patients and also analysed detailed X-ray fibre diffraction and different amyloid diseases were characterised by patterns that she collected from Val30Met transthyretin the nature of the component protein and the location of amyloid fibrils, known to cause familial amyloidotic the deposits. When I joined Colin Blake’s group in the polyneuropathy (4). In collaboration with David Booth Laboratory of Molecular Biophysics in Oxford in late and Vittorio Bellotti, who were working with Mark 1993, to start postdoctoral work on familial lysozyme Pepys in London, we started