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Dr Stephen Roberts

Lecturer in membrane transport

Stephen Roberts

Furness Building



Tel: +44 1524 593145

Research overview

My research expertise is the application of electrophysiological and molecular biological techniques to understand the regulation of ion transport across the biological membranes. I currently use fungal and yeast cell as well as animal cell expression systems (CHO and HEK cells). My research interests have more focussed on anion efflux and Ca2+ influx across the plasma membrane of fungal cells towards identifying and evaluating potential new drug targets. More recently I have collaborated with collegues in the Physics and Engineering departments (Lancaster University and Warwick Uinversity) to investigate the role of transmembrane voltage in signal transduction and the physical origins of selectivity of ion channel.

Research Interests

The major research interests of my group concern the regulation of ion transport across the biological membranes of plant and fungal cells. Current areas of interest include:

Physical origins of selectivity and permeation of ion channels

I currently collaborate with the Medical Physics Group (Lancaster; headed by Professor McClintock) to investigate fundamental properties of ion channels. Specifically, we have recieved EPSRC funding to develop a novel biophysical model towards understanding of ion permeation through ion channels. My role in this collaboration is to perform electrophysiological recordings of Na+ selective channels expxressed in CHO cells and HEK cells.  Site-directed mutagenesis and synthetic biology (generation of unique concatemers) is also employed to test predictions and validate the model.


Organic acid secretion and nutrient acquisition

Organic acid secretion from higher plant roots and fungi into the soil solution plays an important role in nutrient acquisition and metal ion detoxification. Surprisingly, the pathways by which organic acids cross the plasma membrane of cells are not well characterised and little is known of the molecular mechanisms that regulate the exudation of organic acids. We are currently characterising anion channel activity in Aspergillus nidulans and the root of Arabidopsis. We have identified a novel organic acid efflux channels in the plasma membrane of Arabidopsis epidermal root cells (e.g. Diatloff et al., 2004) and Fungi (e.g. Roberts et al. 2013). The regulation of these channels suggest that these transporters probably play a role in phosphate acquisition and other nutrient acquisition.

Calcium signalling in filamentous fungi

Fungi are a diverse but discrete group of organisms with a myriad of activities, many of which impact both directly and indirectly on mankind. Thus understanding how these organisms respond and adapt to their environment is of fundamental importance. Cytosolic Ca2+ has been established as a ubiquitous intracellular signal molecule, essential for the transduction of a wide variety of environmental stimuli in eukaryotic cells. However, despite a strong body of evidence showing key roles for Ca2+ signal transduction in filamentous fungi, our understanding of Ca2+ signalling in these organisms is not well developed. One of the main reasons for this is our current ignorance of Ca2+-permeable channel activity (which is responsible for mediating cytosolic Ca2+ signalling events) in filamentous fungi. Work is ongoing to address this fundamental gap in our knowledge; namely, to identify and functionally characterise Ca2+ permeable channels in filamentous fungi. This work is taking advantage of recent developments in fungal genomics, initially leading to the identification of a number of candidate genes that are likely to encode Ca2+ permeable ion channels (and thus play key roles in Ca2+ signalling) in the model filamentous fungus, Aspergillus nidulans. A multidisciplinary approach, combining a range of molecular biological and cell biological techniques, is being employed.




Current Teaching

I am Divisional director for our international teaching partner (Sunway University) and I oversee delivery and assessment of Dual Lancaster awards at UG and PG levels.

Currently I teach on the following modules:

BIOL121 Impact of Microbes: I cover Fungi. I module organise.

BIOL201 Biochemistry: I cover Citric Acid Cycle, Amino Acid Metabolism and Bioenergetics. I module organise.

BIOL211 Cell Biology: I cover Membrane Transport (Ion Channels, Carriers and Pumps)

BIOL302 Signalling Transport and Disease: I build on second year material and focuss on ion channels in human physiology and discuss ion channel diseases.

BIOL387 Bioscience Research Project: Student projects in Cell Biology with a focus on Ion Channels. These projects are research based and have contributed to at least 3 papers recently (with student acknowledgement as a co-author).


Additional Information


2000         Wellcome Trust Research Career Development Fellowship The role of plasma membrane ion channels in fungal growth - potential targets for fungicides                                                     £311,656

2001         Lancaster University Small Grant Scheme Purchase of equipment for novel investigations of transporters in fungal membranes (directly contributed to successful BBSRC award 2003)         £6096

2001         BBSRC Committee Studentship award for investigation of anion transport in Arabidopsis roots

2001         BBSRC project grant Release of organic acid to the rhizosphere: a role for anion channels.(with Professor D Sanders and Dr M. Roberts)                                                                             £209, 216

2002        BBSRC equipment grant Using modern molecular and cellular techniques to interpret plant responses to environmental change (Co-applicant with Professors RD Bardgett, WJ Davies, AM Hetherington, BG Forde and PJ Lea, and Drs JE Taylor, ND Paul, MR McAinsh).                                                                                                                                    £1,053,816

2003         BBSRC grant “Developing Pichia pastoris as a heterologous expression system for ion transporters” (with Professor B Forde)                                                                                                  £99, 169

2004         Knowledge Transfer Partnership (KTP) award part funded by the Department for Trade and Industry (via the BBSRC) and Micap plc. Developing novel encapsulation technology to protect and control the release of active ingredients from yeast.  (with Dr C Price)                                                     £135,323.

2009         Research and Enterprise Services (Lancaster University) award to identify transmembrane anion transporters responsible for citric efflux from Aspergillus niger                          £2000

2010         Research and Enterprise Services (Lancaster University) award to identify transmembrane anion transporters responsible for citric efflux from Aspergillus niger  (extension)      £3500

2010         University Hospitals of Morecambe Bay NHS Foundation Trust funded (Leese bequest) studentship - Modelling the role of the endothelium in cardiovascular physiology (with Dr J Owen-Lynch and Professor A Stefanovska)                                                                                                           £61,000

2014         Faculty Research Investment Fund (FHM, Lancaster University) Synthesis and functional expression of a novel NaChBac concatamer (with Michael Ginger)                                                            £2100

 2014   EPSRC project grant Ionic Coulomb blockade oscillations and the physical origins of permeation, selectivity and their mutation transformations in biological ion channels (Co-Investigator with Medical Physics Group, Physics Department – Professors PVE McClintock and A. Stefanovska, Drs D Luchinsky and I Kaufmann)                                                       £993,065


2015   Sensory perception in Acanthameoba cyst: molecular mechanisms and electrophysiological properties. (co-Investigator with Dr Siddiqui and Professor Khan at Sunway University)


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