Dario Alessi - SCILLS - The Scottish Institute for Cell Signalling

Professor Dario Alessi

T: 44 1382 385602

F: 44 1382 223778

Professor Dario Alessi FRS, FRSE - Honorary Programme Leader

Research

Understanding the functions of components of the ubiquitin system implicated in human disease
The focus of our laboratory is to uncover the function of signal transduction elements whose mutation causes human disease. Our strategy is to work on poorly characterised components of signal transduction pathway that are linked human disease. The hope is that this information will lead to new fundamental understanding of the causes of disease that can be exploited to develop new approaches to better treat or even cure these conditions. Our laboratory utilises the state of the art biochemistry, mouse genetics-physiology, mass spectrometry and signal transduction technology to address these questions. In previous work our laboratory has established the functions of protein kinases relevant to understanding cancer and diabetes (PDK1 & LKB1), high blood pressure (WNK1) and Parkinson’s disease (LRRK2) (See http://www.ppu.mrc.ac.uk/research/?pid=2).

We now wish to put our experience in studying signalling pathways to use in dissecting the function of proteins that have been linked to human disease in the ubiquitin system. There are two projects we are initially interested in.

Fbx07 Project
Recent work studying a group of PD patients from Iran, Holland and Italy has strikingly revealed that mutation in a previously unstudied gene termed Fbx07 causes very debilitating early onset disease from about 15 years of age [1-3]. The domain structure and location of mutations is indicated in Figure 1. Other Fbx proteins are known to function as critical components of E3 ligases called Cullins. These play vital roles in regulating the ubiquitination and hence stability of target proteins within cells. As the role of Fbx07 is completely unknown, one of the projects we wish to undertake is to generate essential reagents to study Fbx07. We will then use these reagents to define which Cullin E3 ligase, Fbx07 interacts with by undertaking various mass-spectrometry based interactor-based screens. It would be very important to understand whether mutations in Fbx07 identified in PD patients affected assembly of Fbx07 into E3 ligases components. The next stage of the project would be to define what proteins in the cells Fbx07 controls ubiquitination and stability and how mutations in Fbx07 affect the ubiquitination and stability of these targets. We would also be very interested to initiate collaborations with clinicians working with PD patients that have mutations in Fbx07 protein and we will attempt to obtain cells from these patients that could be used to study how mutations in Fbx07 affects identified targets. Using state of the art methodology it is now possible to differentiate these cells into brain neuronal cells and we could use these to further understand how Fbx07 mutations impact on the physiology of these cells to further understand links between Fbx07 and PD. The hope is that we will be able to use the information derived from this project to elaborate new strategies of how Parkinson’s disease may be better treated. This project will tie in nicely with other research we are undertaking in the Parkinson’s disease field to uncover the roles of the LRRK2 and PINK1 protein kinases (see http://www.ppu.mrc.ac.uk/research/?pid=2). It would be exciting if we could uncover a link between fbxo7 and LRRK2/PINK1 or other protein linked to Parkinson’s disease.

Domain structure of fbx07 and location of Parkinson's Disease causing mutations

Dub Project
Like phosphorylation, ubiquitylation is reversible, deubiquitylation being catalysed by isopeptidases, termed deubiquitylases or DUBs. There are ~90 human DUBs which is comparable to the number of protein phosphatases. There are five separate gene families of DUBs, four of which are cysteine proteinases (the USP, OTU, UCH and MJD), the fifth (JAMM/MPN) being metallo-proteinases [4]. DUBs play crucial roles in regulating overall levels of ubiquitylation on proteins and are seen by the pharmaceutical industry as one of the most tractable targets in the ubiquitin system, as there is the expectation that it should be possible to generate relatively specific compounds that target the catalytic sites of these enzymes. Recent unpublished work has identified an uncharacterized DUBs that is involved in cancer that we are very interested to study its regulation and function as well as its importance in cancer. We also wish to explore new methods to quantitatively assay DUB activity and assess and substrate specificity.

Future Projects
With the rapid advances and decreasing costs of analysing human genome sequences, many new disease-causing mutations encoding components of ubiquitin system are likely to be uncovered in the near future. These breakthroughs will provide extraordinary opportunities to dissect new signal transduction pathways that are relevant to the understanding and treatment of disease.

References
1. Di Fonzo, A., Dekker, M. C., Montagna, P., Baruzzi, A., Yonova, E. H., Correia Guedes, L., Szczerbinska, A., Zhao, T., Dubbel-Hulsman, L. O., Wouters, C. H., de Graaff, E., Oyen, W. J., Simons, E. J., Breedveld, G. J., Oostra, B. A., Horstink, M. W. and Bonifati, V. (2009) FBXO7 mutations cause autosomal recessive, early-onset parkinsonian-pyramidal syndrome. Neurology. 72, 240-245.
http://www.ncbi.nlm.nih.gov/pubmed/19038853

2. Shojaee, S., Sina, F., Banihosseini, S. S., Kazemi, M. H., Kalhor, R., Shahidi, G. A., Fakhrai-Rad, H., Ronaghi, M. and Elahi, E. (2008) Genome-wide linkage analysis of a Parkinsonian-pyramidal syndrome pedigree by 500 K SNP arrays. Am J Hum Genet. 82, 1375-1384.
http://www.ncbi.nlm.nih.gov/pubmed/18513678

3. Paisan-Ruiz, C., Guevara, R., Federoff, M., Hanagasi, H., Sina, F., Elahi, E., Schneider, S. A., Schwingenschuh, P., Bajaj, N., Emre, M., Singleton, A. B., Hardy, J., Bhatia, K. P., Brandner, S., Lees, A. J. and Houlden, H. (2010) Early-onset L-dopa-responsive parkinsonism with pyramidal signs due to ATP13A2, PLA2G6, FBXO7 and spatacsin mutations. Mov Disord. 25, 1791-1800.
http://www.ncbi.nlm.nih.gov/pubmed/20669327

4. Nijman, S. M., Luna-Vargas, M. P., Velds, A., Brummelkamp, T. R., Dirac, A. M., Sixma, T. K. and Bernards, R. (2005) A genomic and functional inventory of deubiquitinating enzymes. Cell. 123, 773-786.
http://www.ncbi.nlm.nih.gov/pubmed/16325574?dopt=Citation