Professor Alex Breeze

Introduction

We combine NMR spectroscopy, cryo-electron microscopy and other structural and biophysical methods to interrogate both normal and disease biology at a molecular level. A major area of interest is the normal and disease-altered signalling mechanisms of fibroblast growth factor receptors (FGFRs) and other receptor tyrosine kinases (RTKs), and the ways these can be targeted in cancer drug discovery. We are also using fragment-based drug discovery approaches to target the Ras-activating protein SOS via a novel binding site that may provide a means to develop therapies against cancers driven by mutant Ras, including serious intractable diseases such as pancreatic cancer.

BioNMR in Leeds comprises instruments at 950, 750 and 600 MHz field strength, all with cutting-edge cryoprobes, and is housed in dedicated facilities that are shared by the Zhuravleva, Tomlinson, Karamanos (from June 2020) and Breeze groups as well as a large, lively and thriving user base within the Astbury Centre and the wider N8 universities user community. We are a member of the Instruct-ERIC consortium of European structural biology infrastructures, which provides subsidised access to our state-of-the-art instrumentation for researchers across Europe and the UK.

Current major projects

• Understanding and targeting aberrant FGFR signalling in cancer and developmental disease
• Allosteric switching mechanisms in receptor tyrosine kinase signalling
• Targeting the guanine-nucleotide exchange factor hSOS1 in mutant Ras-driven cancers
• Structural biology of Rab46 GTPases as novel endothelial targets in cardiovascular disease

Detailed research programme

Fibroblast growth factor receptor signalling in cancer

We are interested in cell signalling from FGFRs and their role in development and cancer. Activated FGFRs initiate cascades of intracellular events leading to proliferation, survival and motility. In collaboration with Prof Matilda Katan (UCL), we are using NMR, cryo-EM and other techniques to understand how oncogenic mutations and other cancer-associated alterations such as gene fusions (e.g. FGFR3-TACC3) alter the normal regulation of FGFR activity. Another area of interest is understanding the dependence of some cancer-mutated forms of FGFR3 on cellular chaperones such as HSP90:Cdc37, and using these insights for developing better targeted molecular therapies. Together with Prof Frank Sobott (Leeds), in a collaboration involving AstraZeneca, we are combining NMR and mass spectrometry to understand the interactions between FGFR and the cell membrane, and the ways in which they influence downstream signalling through the adaptor protein FRS2.

Allosteric switching mechanisms in receptor tyrosine kinase signalling

A longstanding enigma in RTK signalling is how binding of homologous but distinct growth factors can trigger very different signalling outcomes, ranging from proliferation through cell survival to enhanced cell motility. We have recently uncovered a potential mechanism that involves a cryptic phosphorylation ‘switch’ within the intracellular kinase domains of FGFRs, which is likely present in many other RTKs (e.g. EGFRs) as well. This switch involves the allosterically-communicated phosphorylation of a tyrosine that is normally occluded, but which once revealed can become a docking site for known effector proteins including PI3-kinase. We are collaborating with Prof Michele Vendruscolo (Cambridge) to combine experimental data from NMR with computational metadynamics to understand the energetic drivers of conformational selection and allostery in bringing about this novel switching mechanism.

Targeting hSOS1 in mutant Ras-driven cancers

Ras family proteins are primarily activated by SOS, which switches them to the ‘on’ state, whence they drive intracellular signalling down proliferative and survival pathways. In many cancers, this process is hijacked by mutations in Ras that jam the switch ‘on’, resulting in runaway cell division – a hallmark of cancer. Together with our collaborators in the CRUK Newcastle Drug Discovery Unit (Prof Mike Waring), with funding from Cancer Research UK, we are using a structure-based drug design approach to exploit a novel ‘druggable’ binding pocket on SOS that affords the potential to inhibit mutant Ras-driven signalling in cancers. If successful, this research could ultimately lead to treatments providing new hope for patients suffering from intractable disease including pancreatic cancer.

Structural biology of Rab46 GTPases

In a project funded by the British Heart Foundation, we are collaborating with Dr Lynn McKeown (Leeds Institute for Cardiovascular and Metabolic Medicine) to elucidate the structural mechanisms underpinning the activity of a novel endothelial cell protein, Rab46, recently discovered in Leeds. Rab46 exerts pleiotropic effects on endothelial cell secretion involving Weibel-Palade bodies (WPBs), as a result of its influence on WPB trafficking. Rab46 is a GTPase that, unusually, contains a number of other domains including coiled-coil and Ca2+-binding EF-hand domains. We seek to understand how the nucleotide-bound status of the GTPase domain is communicated to the EF-hands, and conversely, how the Ca2+-bound status of the EF-hands influences the GTPase domain, in response to pro-inflammatory stimuli including histamine.