The overall objective of our research is to understand the principles governing protein homeostasis - the ability of cells to generate and regulate the levels of proteins in terms of conformations, interactions, concentrations and cellular localisation.

By adopting the strategy of analysing the origins of specific diseases to inform us about normal biology, we have set up an interdisciplinary programme that involves bringing together methods and concepts from chemistry, physics, engineering, genetics and medicine. We are using a combination of in vitro, in silico and in vivo approaches to study protein homeostasis through the analysis of the effects that result from its alteration in a select group of specific proteins, from either amino acid mutations, or changes in concentration and solubility, or the interactions with other molecules. This programme is generating new insights into the mechanism through which physical and chemical sciences can address biological questions in order to understand the normal behaviour of living systems. In addition it is increasing our understanding of the nature and consequences of the failure to maintain homeostasis, which is associated with such phenomena as ageing and neurodegenerative disorders.



LATEST RESEARCH


Structure of an intermediate state in protein folding and aggregation Science 336, 362-368

Protein-folding intermediates have been implicated in amyloid fibril formation involved in neurodegenerative disorders. However, the structural mechanisms by which intermediates initiate fibrillar aggregation have remained largely elusive. To gain insight, we used relaxation dispersion nuclear magnetic resonance spectroscopy to determine the structure of a low-populated, on-pathway folding intermediate of the A39V/N53P/V55L (A, Ala; V, Val; N, Asn; P, Pro; L, Leu) Fyn SH3 domain. The carboxyl terminus remains disordered in this intermediate, thereby exposing the aggregation-prone amino-terminal β strand. Accordingly, mutants lacking the carboxyl terminus and thus mimicking the intermediate fail to safeguard the folding route and spontaneously form fibrillar aggregates. The structure provides a detailed characterization of the non-native interactions stabilizing an aggregation-prone intermediate under native conditions and insight into how such an intermediate can derail folding and initiate fibrillation.

Amyloid-like aggregates sequester numerous metastable proteins with essential cellular functions. Cell 144, 67-78 (2011).

Protein aggregation is linked with neurodegeneration and numerous other diseases by mechanisms that are not well understood. Here, we have analyzed the gain-of-function toxicity of artificial beta sheet proteins that were designed to form amyloid-like fibrils. Using quantitative proteomics, we found that the toxicity of these proteins in human cells correlates with the capacity of their aggregates to promote aberrant protein interactions and to deregulate the cytosolic stress response. The endogenous proteins that are sequestered by the aggregates share distinct physicochemical properties: They are relatively large in size and significantly enriched in predicted unstructured regions, features that are strongly linked with multifunctionality. Many of the interacting proteins occupy essential hub positions in cellular protein networks, with key roles in chromatin organization, transcription, translation, maintenance of cell architecture and protein quality control. We suggest that amyloidogenic aggregation targets a metastable subproteome, thereby causing multifactorial toxicity and, eventually, the collapse of essential cellular functions.

NEWS

Cambridge-Elan Centre



The Cambridge-Elan Centre for Research Innovation and Drug Discovery has been launched.


NEW TOOLS

d2D: Determination of secondary structure populations in disordered states of proteins using NMR chemical shifts.



C. Camilloni, A. De Simone, W. Vranken and M. Vendruscolo. Biochemistry 51, 2224-2231 (2012).


BOOKS

Networks in Cell Biology



M. Buchanan, G. Caldarelli, P. De Los Rios, F. Rao and M. Vendruscolo (Eds). Cambridge University Press, Cambridge (2010).