Exploring a new paradigm for endocytic trafficking and K+ channel function in cells
Lead Research Organisation:
University of Leeds
Department Name: Sch of Molecular & Cellular Biology
Abstract
All viruses must infect cells in order to make copies of themselves and infect new cells. To achieve this, viruses use the machinery of host cells to create an environment that favours their own survival. Through understanding how viruses interact with the cells they infect, we can gain important knowledge as to how cells themselves work.
We have discovered that during infection, certain viruses need access to potassium, which is present inside cells. The potassium changes the structure (shape) of the viruses into more infectious forms. This potassium is delivered by proteins in the cells that are called potassium channels, of which there are approximately 80 different types in the human body.
Our proposed research aims to find out which potassium channels are exploited by viruses to infect human cells, and if blocking them with drugs prevents infection. Once we have identified the potassium channels that are needed by the virus, we then want to understand why the cells have these channels, and if the potassium is also changing the structures of cellular proteins to alter their function, just like that observed for viruses.
By completing these experiments, we may reveal new fundamentally important roles of potassium in cells that will increase our understanding of how our cells work. We may also reveal potassium channels as a new and exciting class of anti-viral targets that can be used to treat diseases caused by viruses.
We have discovered that during infection, certain viruses need access to potassium, which is present inside cells. The potassium changes the structure (shape) of the viruses into more infectious forms. This potassium is delivered by proteins in the cells that are called potassium channels, of which there are approximately 80 different types in the human body.
Our proposed research aims to find out which potassium channels are exploited by viruses to infect human cells, and if blocking them with drugs prevents infection. Once we have identified the potassium channels that are needed by the virus, we then want to understand why the cells have these channels, and if the potassium is also changing the structures of cellular proteins to alter their function, just like that observed for viruses.
By completing these experiments, we may reveal new fundamentally important roles of potassium in cells that will increase our understanding of how our cells work. We may also reveal potassium channels as a new and exciting class of anti-viral targets that can be used to treat diseases caused by viruses.
Technical Summary
This proposal describes experiments that will reveal critical new information regarding the regulation of cellular endocytic pathways and the molecular mechanisms of virus entry.
Receptors and pathogens use the changing environment of maturing endosomes as cues to deliver their cargo to the appropriate cellular location. It is now known that potassium accumulates along the endocytic pathway and we have shown that potassium ions work in concert with the acidic pH of maturing endosomes to induce dramatic changes to the viral fusion proteins of bunyaviruses. These changes are required for these viruses to escape endosomes, but there is a distinct lack of knowledge about how and why endosomes accumulate potassium in their native cellular context.
We propose to perform a detailed molecular dissection of a cellular channel that we believe controls endosomal potassium accumulation that we have recently identified using viruses as intracellular tools. We will assemble a panel of reagents to inhibit this channel and use these as pharmacological tools to understand if endosomal potassium influences the fate of internalised receptor-ligand complexes that transverse the endosomal system, or whether it is solely a process that viruses co-opt during infection.
This work represents critical basic science that is required in order to fully understand the roles of endosomal potassium in health and disease, but with the potential to facilitate the development of drugs that inhibit virus entry. The impact of this work will be wide reaching with relevance to the BBSRC 'Systems approaches to the biosciences' and 'Animal health', which are the main themes within our strategic plan. Understanding the role of endosomal potassium will produce a step-change in our understanding of endocytosis and enable the pursuit of other higher-level questions regarding both endocytic cargo and virus trafficking.
Receptors and pathogens use the changing environment of maturing endosomes as cues to deliver their cargo to the appropriate cellular location. It is now known that potassium accumulates along the endocytic pathway and we have shown that potassium ions work in concert with the acidic pH of maturing endosomes to induce dramatic changes to the viral fusion proteins of bunyaviruses. These changes are required for these viruses to escape endosomes, but there is a distinct lack of knowledge about how and why endosomes accumulate potassium in their native cellular context.
We propose to perform a detailed molecular dissection of a cellular channel that we believe controls endosomal potassium accumulation that we have recently identified using viruses as intracellular tools. We will assemble a panel of reagents to inhibit this channel and use these as pharmacological tools to understand if endosomal potassium influences the fate of internalised receptor-ligand complexes that transverse the endosomal system, or whether it is solely a process that viruses co-opt during infection.
This work represents critical basic science that is required in order to fully understand the roles of endosomal potassium in health and disease, but with the potential to facilitate the development of drugs that inhibit virus entry. The impact of this work will be wide reaching with relevance to the BBSRC 'Systems approaches to the biosciences' and 'Animal health', which are the main themes within our strategic plan. Understanding the role of endosomal potassium will produce a step-change in our understanding of endocytosis and enable the pursuit of other higher-level questions regarding both endocytic cargo and virus trafficking.
