Award details

MicA, a novel protease adaptor in metabolic shutdown.

Reference	BB/S006877/1
Principal Investigator / Supervisor	Dr Rivka Isaacson
Co-Investigators / Co-Supervisors
Institution	King's College London
Department	Chemistry
Funding type	Research
Value (£)	448,531
Status	Current
Type	Research Grant
Start date	01/06/2019
End date	31/05/2023
Duration	48 months

Abstract

In health and disease cells sometimes change their identities by closing down one set of genes and activating another. Studying these tightly-controlled transitions at a molecular level is vital for defining their precise mechanisms and ultimately designing drugs that can interfere with them. A protein, MicA, newly discovered by our collaborator, acts as a novel adaptor for the protease, ClpC, and plays a vital role in effecting metabolic shutdown in a canonical identity change in the tractable model organism Bacillus subtilis, whereby the bacteria become dormant long-lived spores to survive stress conditions. From a genetics perspective this transition has been well-characterised in B. subtilis but the mechanistic gaps that remain can only be filled using the molecular approach proposed here. Forespore metabolism must shut down for the spore to become dormant but the mechanisms for this process are still elusive. MicA is involved in shutting down metabolism in the forespore while components still required to complete the process are supplied by the mother cell through a 'feeding tube'. Here I will investigate this system by solving structures of MicA and its complex with ClpC. I will identify MicA substrates and probe this molecular mechanism using biophysical techniques to learn precisely how MicA effects its function and I propose to identify its substrate/s. In concert with my microbiology collaborators we will shed light on this important part of the sporulation process and investigate the clear likelihood of MicA being a target for antimicrobial development. This work will increase basic understanding of cell differentiation and has specific implications for combating the problem of 'hospital superbugs' which can persist in hardy spore form evading heat and disinfectant.

Summary

We propose to study the way cells can completely transform their identity by activating a 'gene expression switch'. Such transformations are important to naturally maintain health e.g. in embryo development which begins with identical cells which then crucially change into the different types of cells that make up a developed human. Conversely, these transformations can cause harm e.g. when cells become cancerous or pathogens invade hosts. A gene expression switch involves a distinct programme of genetic instruction being deactivated and replaced with an alternative that leads to radical transformation of the cell's nature. In this study my group will examine a newly discovered protein, MicA, which acts an adaptor to the protease ClpC during bacterial spore formation. We have evidence that MicA is involved in metabolic shut-down as the spore becomes dormant. Sporulation is partially responsible for the persistence of 'hospital superbugs' as spores are a long-lived bacterial form, resistant to cleaning agents and thriving in patients depleted of natural gut microflora. We intend to uncover the detailed molecular shapes of MicA when it is free and bound to ClpC using indirect techniques as they are too small to see even using powerful microscopes. We specialise in measuring protein shapes and the way they fit together by producing them artificially in large quantities, with the help of bacteria which act as our 'protein factories'. We then deduce the proteins' molecular structures by processing their behaviour when we bounce X-rays off them or put them in strong magnetic fields. Each of these techniques has its strengths and weaknesses but our combined approach can yield complementary information filling in the gaps left by using just one of the methods. Collaborating with a microbiologist we will feed information into each others' experiments to build up a mechanistic picture of this gene expression switch in bacterial spore formation. For example, if we identify amutation in one of our proteins that makes it bind more tightly to its partner our collaborator can make the same mutation within bacteria to test whether it has the predicted effect in living systems. By solving this jigsaw puzzle we hope to be in a stronger position to design novel antibiotics to attack the increasing problem of bacterial drug resistance and the project also has longer term implications for understanding metabolism and gene expression switches in many aspects of health and disease.

Impact Summary

The proposed research will have shorter and longer-term impact on Society and the economy: SHORTER-TERM IMPACT: My move to the chemistry department at King's has already begun to generate new experimental ideas through combining interdisciplinary expertise with local colleagues. This study will thus have impact on research methods in the chemistry community as discussed in my 'academic beneficiaries' section and there will be knock-on effects from any discovery resulting from use of these techniques by other groups. I have a longstanding commitment to Public Engagement, described in more detail in my Pathways to Impact statement and I have plans to disseminate my findings in non-scientific settings through the written and spoken word creating social impact by making the non-scientifically trained public better-informed about science while feeding back their ideas into the creativity of scientific planning. Since I am now at a University that teaches Arts subjects as well as science there is also far more opportunity for creating radically interdisciplinary impact and I am currently meeting with arts colleagues (English, psychology and education departments) to prepare an application for King's Together, a fund specifically designed for this. My last successful BBSRC application included a £10K public engagement budget to fund a pilot science/arts project with London Fine Art Studios to explore common methodology between artists and scientists. Thanks to the goodwill of contributors we managed to maximise this budget beyond our expectations and we have produced six portraits of people who either perform, communicate or facilitate science (including best-selling novelist, gamer and science presenter, Naomi Alderman, and Julian Huppert, physicist, ex-MP). We made wonderful films of the creative process with the artists and sitters discussing their techniques and identifying common ground. We are currently pitching an immersive, multimedia, public exhibition, to major London venues, that will directly engage a large number of people with diverse backgrounds and education. We are requesting a further £10K public engagement budget here to develop our show further, run a programme of educational events including panel discussions and hand-on workshops, and take it on the road following its debut in London so that it will reach communities all over the UK. This is will generate positive publicity for structural biology (exposing new audiences to the beauty of molecular structures) and the research councils. LONGER-TERM IMPACT: The more information we have, on the detailed workings of the cellular transformation and metabolism, the stronger is our potential to combat disease and promote health and well-being in the population. In this research programme my group will examine aspects of metabolic shutdown in sporulation that have never yet been studied in three-dimensional molecular detail. The results will potentially be significant in providing the basis for novel antibiotic development. This could provide economic benefit to the NHS and health care providers in preventing the use of inappropriate drugs and the development of new, more specific, ones in the challenging area of antimicrobial resistance.

Committee	Research Committee D (Molecules, cells and industrial biotechnology)
Research Topics	Microbiology, Structural Biology
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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