A Multi-Purpose Protein Expression Platform

Martinez-Costas_JoseJosé Martínez-Costas, PhD, Associate Professor at the University of Santiago de Compostela, spoke with Cambridge Healthtech Institute about his team’s work on a new tagging platform to overcome the bottlenecks in protein expression and production. Dr. Martínez-Costas will be speaking during the Optimising Expression Platforms conference at PEGS Europe, 18-19 November 2019.

1. What is the biggest bottleneck in protein expression & production?

There are several identified bottlenecks in protein expression. Being the most commonly reported: i) purification of insoluble proteins, ii) expression of glycoproteins and membrane proteins, in particular multi-domain membrane proteins, and iii) toxic proteins, that is, proteins whose overexpression is deleterious for the expressing cell or that have a negative effect on the expression method used, not necessarily meaning cell death.

2. How does the IC-Tagging platform your team developed overcome these challenges?

As we purify microspheres (MS) we do not depend on protein solubility to get a result, as far as you can use it as part of the MS. Also, we have demonstrated that proteins keep their activity while integrated inside the MS. With our methodology we have obtained membrane proteins and glycoproteins. The peptide that makes the scaffold for the MS is meant to hold all the necessary components for avian reovirus replication, so it can accommodate many different entities. On the other hand, integration into MS separates a protein from its natural environment inside the cell, which can help in the expression of toxic and difficult-to-express proteins.

3. Can the IC-Tagging platform be applied beyond IGRP expression for type 1 diabetes research?

Thanks to their innate adjuvant activity, the MS can be used for trying to develop “tolerogenic” vaccines for IGRP and other auto-antigens that cause diabetes. One can also consider the possibility of encapsulating insulin inside the MS, either alone or helped by polymeric envelopes, to obtain formulations of edible insulin.

4. What other protein expression platforms show promise?

In general, any other expression methodology that helps in the purification of proteins is good, especially tags that help in the solubilization of proteins that usually don´t go in solution. Also, methodologies that keep the expression tightly controlled are helpful in the expression of difficult proteins. All those can act synergistically with IC-Tagging as, to the best of my knowledge, there is no methodology that works in a similar way to ours.

José Martínez-Costas, PhD, Associate Professor, Departamento de Bioquímica e Bioloxía Molecular, Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS)

I carried out my PhD at the Department of Biochemistry and Molecular Biology, University of Santiago under the supervision of Professor Javier Benavente. In January 1994 I moved to the laboratory of Dr. Polly Roy (Oxford, UK) working with Bluetongue Virus (BTV). In September 1996 I returned to the University of Santiago where I became Associate Professor in 2003. Since 2012 I received the accreditation for full professorship. Our group has been dedicated to studying the molecular biology of avian reoviruses, as well as the molecular mechanisms that regulate their interactions with the host cell. In the course of those studies we have developed and patented the multi-purpose IC-tagging platform and showed its value for production of adjuvant-free vaccines, immobilized heat-stable enzymes, and difficult proteins. We also keep close collaboration with several groups on the development of bio-active organic molecules.