We are interested in protein-protein interactions and the ways in which the affinity and specificity of such interactions can be manipulated. Our studies include computational and experimental approaches, ranging from the atomic design and characterisation of novel binding modules to the re-wiring of cellular pathways. Our current areas of research are described in more detail below.


Protein based biomaterials for tissue engineering

A “one size fits all” biomaterial no longer exists, and the value rests in the customization of material design. The Regan Lab is using modular protein building blocks crosslinked using the SpyTag/SpyCatcher peptide/protein pair to build functional biomaterials for tissue engineering. Protein based biomaterials present macroscopic properties encoded in the microscopic properties of their biological components and they can be customised to suit a particular environment and tissue. We have successfully designed and programmed engineered proteins to form biomaterials with defined physical characteristics (e.g mechanical strength, gelation speed, swelling) able to sustain cell culture without loss of cell viability. The genetically encoded SpyTag/SpyCatcher chemistry allows us to easily incorporate different recombinant proteins in the biomaterials and induce a wide array of controlled biophysical characteristics. In the future we are looking into further altering the characteristics of the biomaterials by altering the key features in the protein sequence to target different organs.

LIVE-PAINT: Using protein-protein interactions for super-resolution imaging in live cells

Fluorescent imaging is a powerful tool for studying protein function in living cells and is traditionally performed by fusing a fluorescent protein to the protein of interest. Unfortunately, fluorescent proteins are relatively large (~30 kD) and can sometimes interfere with a protein’s native function and location. Additionally, unless PALM is used, the resolution of the images generated using direct fusions is limited, which could affect colocalization studies.

The Regan lab in collaboration with the Horrocks lab has developed a novel, less perturbative method for super-resolution imaging proteins in vivo called LIVE-PAINT. This method is based on transient interactions between a peptide tag and a partner protein. The peptide is fused to the C-terminus of a protein of interest, while the partner protein is fused to a fluorescent protein and expressed in the same cell. During imaging, ‘blinks’ are observed whenever the peptide-protein pair interact. The precise location of each of these blinks can be determined during analysis, resulting in a super-resolution image of the protein of interest.

We have demonstrated that this system is functional in bacteria and budding yeast for imaging a variety of different proteins, including those that do not tolerate a direct fusion to a fluorescent protein. In collaboration with the Rosser lab, we are currently working to move this imaging strategy into mammalian cells.

Biological selection without cells: high-throughput cell-free devices with protein-based tools

We propose to exploit the power of biology, by establishing a new paradigm for cell-free protein synthesis and phenotypic screening, which will enable us to perform biological selection without cells.

This area of research combines state-of-the-art expertise from the Regan and Laohakunakorn groups in key areas (nanotechnology/surface-engineering, protein structure and function, combinatorial targeted mutagenesis, cell-free protein synthesis and microfluidics) to tackle the creation of proteins with user-specified activities, at a time where the desire for biological, renewable solutions to the world’s problems is high. Imagine, for example, that one could create proteins that block viral infectivity, that allow plants to be cultivated that are resistant to disease, that allow protein-based therapeutics to be produced in a streamlined fashion. Imagine that one could produce proteins that have ideal kinetic properties for intracellular visualisation of cellular function, that control cellular function at the level of the proteome, rather than at the level of transcription, or proteins that catalyse novel, commercially important reactions. The list is endless. But before that can happen, we must establish a seamless method that combines these methods to achieve the overall goal. No-one has tried to combine all these unique components before. Our team has the expertise and synergy to do just that.


BslA proteins (shown in blue) can spontaneously form monolayers on the surface of glass. We can use these protein monolayers to covalently capture proteins from solution to the surface using the SpyTag/SpyCatcher chemistry (shown in orange). This is especially useful for cell-free protein synthesis applications, as it can provide a straight-forward in situ purification method.