11.10.2021: Meet Ronald Clarke - Recipient of the 2021 SURFE²R N1 Research Grant
Meet Ronald Clarke
Earlier this year, Nanion announced the SURFE²R N1 research grant, which gave applicants the opportunity to acquire a SURFE²R N1 instrument for a 9-month period; inclusive of consumables, training and consultation.
After a lenghty and throughout evaluation of the rather extensive number and variety of applications, the SURFE²R N1 grant evaluation committee Dr. Andre Bazzone, Dr. Cecilia George, and Dr. Maria Barthmes (Nanion Technologies) have come to a decision:
2021 SURFE²R N1 Research Grant Committe
(Dr. Andre Bazzone, Dr. Cecilia George, and Dr. Maria Barthmes)
We were overwhelmed by the number and quality of the proposals this year and we thank all of the applicants for putting in such a lot of time and effort in their applications. We had a very difficult job but we thoroughly enjoyed reading each and every one of the proposals. As such, we took the bold initiative to award an unprecedented four total winners! We would like to congratulate Jonai Pujol (Winner - Europe), Edmund Kunji (Winner - UK), Lei Zheng (Winner - North America), and Ronald Clarke (Winner - Australia)
We have created a plan to deliver the systems to their respective labs, which we hope will be later on this year (COVID-19 permitting) and are excited for their research initiatives to begin. Additionally, we aim to provide external support to all applicants in the near future and have created a plan to provide local support from our offices in Europe, North America, Japan and China.
We look forward to supporting the Membrane Transporter Community and leading the way with all of your innovative ideas in the months to come.
Interview with Ronald Clarke, University of Sydney, Australia
Hi Ronald, congratulations on your win! What are you planning to do with SURFE²R N1 in your laboratory?
Ronald Clarke: “We plan to investigate the role played by animal plasma membrane asymmetry in the regulation of the activity of P-type ATPases, in particular the Na+,K+-ATPase and the gastric H+,K+-ATPase. Both these ion pumps possess clusters of basic amino acid residues (mainly lysine) at their N-termini. It has been hypothesized that such clusters could help to regulate the pumps via an electrostatic switch mechanism involving a change in interaction of the basic clusters with negatively charged lipid headgroups on the surrounding membrane. The negative charge of the cytoplasmic surface of the membrane is normally maintained by flippases within the membrane, which transport phosphatidylserine (PS) from the extracellular leaflet of the plasma membrane to the cytoplasmic leaflet and prevent PS exposure on the extracellular face of a cell. PS exposure normally only occurs when a cell is about to undergo apoptosis. Thus, the electrostatic switch mechanism potentially provides a link between apoptosis and ion pump activity, which could enable pumps to be shut down to avoid energy wastage when a cell is about to be disposed of.
With the SURFE²R we plan to carry out investigations of the effect of the pumps’ N-terminus on ion transport activity. We will compare capacitive currents generated by the pumps before and after specifically targeted tryptic cleavage of the N-termini from the rest of the protein. We will also investigate the effect of changing the net charge on the ion pumps’ N-termini by regulatory phosphorylation of conserved serine residues by protein kinase C.
The knowledge that we gain will provide fundamental new information on the mechanism of ion pump regulation, which we hope could provide an understanding of diseases in which these pumps are implicated, e.g., cancer, cardiovascular disease, diabetes, as well as stimuli for drug design targeting ion pumps.”
Nanion: Why did you apply for the SURFE²R N1 Grant?
Ronald Clarke: “I was already aware of the capabilities of the SURFE²R instrument from my time working at the Max-Planck-Institute of Biophysics in Frankfurt/Main, where the technology on which the SURFE²R is based was developed by Dr Klaus Fendler. At ion pump conferences I have also often seen fine work presented using the instrument, in particular by Dr. Francesco Tadini-Buoninsegni from the University of Florence. Therefore, I knew that the instrument provides very useful data on electrogenic charge transport by ion pumps. In my own research up to now I have studied ion pumps by calorimetric and optical means, detecting charge transport via voltage-sensitive fluorescent dyes. After seeing the announcement of the SURFE²R grants I decided to apply because it would enable me to widen the scope of my research to include complementary electrophysiological studies. Another attractive aspect was the opportunity to introduce this new technology to the Australian biophysical community, where no-one currently has an instrument, and hence the scope exists for establishing new collaborations with other ion pump researchers around Australia.“
Nanion: Which properties of the SURFE²R will be of benefit to your research?
Ronald Clarke: “The major benefit is that the SURFE²R allows one to measure electrogenic transport events of ion pumps and transporters in cell-free systems, using membrane fragments and lipid vesicles. The turnover numbers of ion pumps and transporters are much lower than the ion fluxes through ion channels. This makes the measurement of pumps and transporters by the more traditional patch-clamp technique very difficult. The SURFE²R overcomes this difficulty by allowing one to measure over a much larger surface area incorporating a much higher number of ion pump or transporter molecules.
Another very significant benefit of the SURFE²R for my research is the ability of constructing the solid-supported lipid bilayer with different lipid molecules. This will allow us to investigate the lipid specificity of ion pump activity and membrane interaction.”
Read more about Ronald Clarke's research here
Watch The Video Announcement - Ronald Clarke (University of Sydney)