We study the mechanism and regulation of protein synthesis in eukaryotic cells. This critical part of the process of gene expression ensures cells decode the genetic information held within the genome and accurately convert these molecular instructions into proteins. Cells only make the proteins they need when and where they are required-how do they do this? Organisms also have to adapt to changing environments and stresses (temperature, sunlight, infection etc) and adapting the set of proteins made by cells contributes to the adaptability of life. How is this achieved? How are these processes impacted by human disease mutations?

We primarily use baker’s yeast (Saccharomyces cerevisiae) as a simple cellular model organism to study the molecular mechanisms controlling how cells regulate the sets of proteins that they require. Because of evolutionary conservation of mechanisms, insights gained from our studies are relevant to human cells and human diseases. We are able to create simple cell models that mimic aspects of human disorders. We have recently expanded our studies into Zebrafish as a vertebrate model of disease.

Protein Synthesis

Protein synthesis is the process of decoding an mRNA sequence into a functional protein. This is central to all cellular activity and is a major energy consumer within all cells. In eukaryotes, protein synthesis or 'translation' is mediated via a highly-conserved set of protein factors which interact with each mRNA and the ribosome. Translation is highly dynamic and must be flexible to change which proteins are made in response to a large number of input signals. Therefore gene expression controls at the level of translation are critical to a large number of normal cellular processes. For example they are important for stress responses, normal development of embryos and for memory formation in the brain.

The Pavitt lab studies aspects of translation and its control using a range of biochemical and genetic approaches. We primarily make use of the yeast Saccharomyces cerevisiae as a model organism with well developed genetic and biochemical tools to study fundemental biochemical processes. The protein synthesis factors we study as well as many of the key regulatory mechanisms are conserved from yeast to man, making findings in yeast directly relevant to human translation. For example we have used yeast to model effects of mutations in translation factors responsible for human diseases affecting eIF2B and eIF5A.

We are now also using zebrafish to model the eIF5A-related neurodevelopmental disorder called FABAS.

Translational Control of eIF2 by eIF2B and eIF5. The molecular mechanism of gene regulation in response to stress is being investigated. A regulatory mechanism, common to all eukaryotic cells, and termed the integrated stress response involves translational control by phosphorylation of translation factor eIF2, a GTP and initiator tRNA binding protein. One key step at the core of the control pathway is the inhibition of the translation factor eIF2B, a guanine nucleotide exchange factor (GEF) (red arrows in the figure). One aim of our work is to understand how eIF2B functions and we have developed a range of biochemical assays to study this. We have identified novel regulatory mechanisms and steps in protein synthesis initiation. For example, we identified that eIF5, has a novel GDP-dissociation inibitor (GDI) activity which antagonises the function of eIF2B and is critical for the response to phosphorylated eIF2. In addition we have found that eIF2B can actively displace eIF5 from eIF2 (GDF function) so that eIF2B can then perform its nucleotide exchange function. We have now shown that eIF2B can also antagonise eIF2 when bound to GTP and tRNA, this we call 'fail-safe control'. In colaboration with the Roseman lab, we have also determined the eIF2/eIF2B co-structure by cryoEM.

mRNA binding proteins and translational control. In collaboration with the Ashe, Grant, Talavera and Hubbard laboratories here at Manchester we are studying translatation factors that control mRNA selection, the eIF4F factors and the eIF4E-BP regulatory proteins Caf20 and Eap1, as well as RNA-binding proteins such as Puf and LARP proteins that modulate translational activity of ribosomes. An imprtant question we are addressing is how do these proteins contribute to translational regulation following cellular stress?

Genetic Disorders. In collaboration with Siddharth Banka and Paul Kasher we are studying how mutations in human translation factors can cause developmental and neurological disorders. We have recently found that de novo mutations in eIF5A cause a novel neurodevelopmental disorder. eIF5A is a regulatory translation factor that binds to the ribosome E site to help resolve translation issues that cause ribosome pauses. Patients exhibit microcephaly and intellectual disability. In model systems we find that the polyamine spermidine can partially rescue eIF5A defects.

Funding: BBSRC, MRC-DTP, Weizmann-UK

Lab group

The Pavitt research group collaborates with several other academic groups within Manchester including

Mark Ashe, Sid Banka, Chris Grant, Simon Hubbard, Paul Kasher, Ray O'Keefe, Martin Pool, Alan Roseman and David Talavera

The group includes the following post-docs and PhD students

• Sophie Mogg
• Jorge Peinado
• Blanca Navarrete
• Carolina Stamboulid
• Matthew Eastham
• Robert Crawford
• Nerys Thornhill
• Jake Rhoads

Graham Pavitt is a Professor within Faculty of Biology Medicine and Health (FBMH). He obtained an Honours degree in Microbiology and Virology from The University of Warwick (1988) and his D.Phil in Biochemistry from the University of Oxford (1992) studying gene expression mechanisms under the direction of Prof. Chris Higgins. Graham undertook postdoctoral studies at the National Institutes of Health, Bethesda USA in Dr Alan Hinnebusch's laboratory, where he developed his interests in translational control. He was funded by a post-doctoral fellowship from the European Molecular Biology organization (EMBO) and then a John Fogerty International Fellowship.

In 1998, Graham returned to the UK with a Career Development Award from the Medical Research Council. He set up his laboratory at the University of Dundee, and in 2000 moved south to Manchester with a University Lectureship within the Biomolecular Sciences Department at UMIST. Following the merger of UMIST and the Victoria University of Manchester in 2004 Graham joined the Faculty of Life Sciences (FLS). He was promoted to Senior Lecturer in 2005, Reader in 2009 and Professor in 2013. FLS merged with Medicine to become FBMH in August 2016.

Graham has built his research group with funding from BBSRC, The Wellcome Trust, the European Leukodystrophy Association and the EU. His work focusses on understanding mechanisms and regulation of gene expression at the translation step - where mRNA is decoded into protein.

Graham has co-organised several national conferences on translation (1999, 2002, 2005, 2008, 2018) and yeast (2001, 2015) and Co-arranged the 2020 Cold Spring Harbor 'Translational Control' meeting that was held virtually because of the Covid-19 pandemic. He has served on the Biochemical Society 'Genes' theme panel (2003-2006) and was a member of the Biochemical Journal Editorial Board (2004-2012). Graham has been awarded two University Distinguished Achievement Awards: Researcher of the Year in 2011 and Teacher of the Year in 2014.