Co-operative gating interactions in the yeast TOK1 K+ channel
Lead Research Organisation:
University of Glasgow
Department Name: Institute of Biomedical & Life Sciences
Abstract
K+ channels play major roles in all living cells, providing a pore, or pathway for K+ ion movements across membranes. How these channels are constructed and the mechanisms by which they regulate (gate) the flow of K+ through their pores is a field of intense research. We know now that the pores of all K+ channels comprise four protein domains, each with a pore loop and two, flanking transmembrane helices. Gating of these channels has generally been thought to arise from independent protein conformational changes within each domain that contribute to opening the pore. The yeast K+ channel TOK1 is gated both by voltage and by extracellular K+. Surprisingly, we recently uncovered evidence of long-distance interactions between putative K+-binding sites associated with each pore loop. The results identify an unanticipated co-operativity between adjacent pore domains and, thus, should provide new insights into the gating of these channels. An extension to the current project will enable us to systematically explore these interactions and their implications for the molecular functioning of the TOK1 K+ channel.
Technical Summary
Understanding the molecular mechanisms of gating in voltage-gated K+ channels remains a major issue in biology. The combination of structural, molecular and cellular methods to their analysis has already yielded some remarkable insights into these processes. We know now that the pores of all K+ channels comprise four protein domains, each with a pore loop and two, flanking transmembrane helices. Gating of these channels has generally been thought to arise from independent conformational changes within each domain that contribute to opening the pore. The yeast K+ channel TOK1 is gated both by voltage and by extracellular K+. Surprisingly, we recently uncovered evidence of long-distance interactions between putative K+-binding sites associated with each pore loop. We had demonstrated previously that the K+-sensitivity of TOK1 is mediated by two, kinetically separate K+ gates with different [K+] dependencies and, apparently, paired K+-binding sites on the outer surface of each pore domain. Quite unexpectly, our studies now have uncovered long-range interactions between K+-binding sites, demonstrating a co-operativity between pore domains in TOK1 channel gating. These data offer the first substantive evidence of a synergy between pore domains in a K+ channel, and are likely to yield important clues to the mechanics of gating in TOK1 and, plausibly, in other K+ channels. Because extracellular K+ clearly interacts with voltage-mediated gating in these channels, we now have a powerful tool with which both to manipulate gating and to probe the associated protein conformations. We will extend our present studies to mapping the cross-interacting domains that affect gating synergistically. A key advantage for these studies will be our use of double mutants that 'rescue' quasi-wild-type characteristics. Experiments will compare the the effects of single and double mutations on synergistic and/or compensatory effects in gating. We will assess the requirement for the intact protein backbone in gating synergy between the pores. Finally, we will examine potential for cross-interaction between TOK1 pore domains on separate polypeptide chains. These experiments will identify residues are critical for cross-interaction between the pore domains and should establish the scope and relationship(s) in pore domain interactions for TOK1 gating.
People |
ORCID iD |
| Michael Blatt (Principal Investigator) |
Publications
Gehl B
(2014)
An Arabidopsis stomatin-like protein affects mitochondrial respiratory supercomplex organization.
in Plant physiology
Grefen C
(2010)
A ubiquitin-10 promoter-based vector set for fluorescent protein tagging facilitates temporal stability and native protein distribution in transient and stable expression studies.
in The Plant journal : for cell and molecular biology
Grefen C
(2010)
A novel motif essential for SNARE interaction with the K(+) channel KC1 and channel gating in Arabidopsis.
in The Plant cell
Grefen C
(2008)
SNAREs--molecular governors in signalling and development.
in Current opinion in plant biology
Grefen C
(2011)
Ion transport, membrane traffic and cellular volume control.
in Current opinion in plant biology
Honsbein A
(2009)
A tripartite SNARE-K+ channel complex mediates in channel-dependent K+ nutrition in Arabidopsis.
in The Plant cell
Honsbein A
(2011)
A molecular framework for coupling cellular volume and osmotic solute transport control.
in Journal of experimental botany
Jezek M
(2017)
The Membrane Transport System of the Guard Cell and Its Integration for Stomatal Dynamics.
in Plant physiology
Jezek M
(2019)
A constraint-relaxation-recovery mechanism for stomatal dynamics.
in Plant, cell & environment
Johansson I
(2006)
External K+ modulates the activity of the Arabidopsis potassium channel SKOR via an unusual mechanism.
in The Plant journal : for cell and molecular biology
Johansson I
(2006)
Interactive domains between pore loops of the yeast K+ channel TOK1 associate with extracellular K+ sensitivity.
in The Biochemical journal
Juric I
(2019)
Computational modelling predicts substantial carbon assimilation gains for C3 plants with a single-celled C4 biochemical pump.
in PLoS computational biology
Karnik R
(2017)
Commandeering Channel Voltage Sensors for Secretion, Cell Turgor, and Volume Control.
in Trends in plant science
Klejchova M
(2021)
Membrane voltage as a dynamic platform for spatiotemporal signaling, physiological, and developmental regulation.
in Plant physiology
Larson ER
(2020)
Synergy among Exocyst and SNARE Interactions Identifies a Functional Hierarchy in Secretion during Vegetative Growth.
in The Plant cell
Larson ER
(2017)
Clathrin Heavy Chain Subunits Coordinate Endo- and Exocytic Traffic and Affect Stomatal Movement.
in Plant physiology
Lawson T
(2014)
Stomatal size, speed, and responsiveness impact on photosynthesis and water use efficiency.
in Plant physiology
Lefoulon C
(2021)
The bare necessities of plant K+ channel regulation.
in Plant physiology
Liao X
(2019)
A FRET method for investigating dimer/monomer status and conformation of the UVR8 photoreceptor.
in Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology
Pantin F
(2018)
Stomatal Response to Humidity: Blurring the Boundary between Active and Passive Movement.
in Plant physiology
Papanatsiou M
(2017)
Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency.
in Journal of experimental botany
Papanatsiou M
(2019)
Optogenetic manipulation of stomatal kinetics improves carbon assimilation, water use, and growth.
in Science (New York, N.Y.)
Riedelsberger J
(2010)
Distributed structures underlie gating differences between the kin channel KAT1 and the Kout channel SKOR.
in Molecular plant
Riedelsberger J
(2017)
Editorial: Roots-The Hidden Provider.
in Frontiers in plant science
Sokolovski S
(2008)
Functional interaction of the SNARE protein NtSyp121 in Ca2+ channel gating, Ca2+ transients and ABA signalling of stomatal guard cells.
in Molecular plant
| Title | EZ-Rhizo |
| Description | Computer software tool for quantitative measurement and analysis of root growth/development |
| Type Of Material | Physiological assessment or outcome measure |
| Year Produced | 2010 |
| Provided To Others? | Yes |
| Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
| URL | http://psrg.org.uk |
| Title | Henry |
| Description | Software for electrophysiology and imaging data aquisition and analysis |
| Type Of Material | Technology assay or reagent |
| Provided To Others? | Yes |
| Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
| URL | http://psrg.org.uk |
| Title | Software tools for electrophysiology and imaging |
| Description | The laboratory continues to develop and refine software/hardware tools for data acquisition and analysis relevant to electrophysiology, single-cell imaging and analysis. These activities are long-standing and open-ended, and develop in line with the current research activities and needs of the laboratory. All software and related packages are made freely available to the research community through the laboratory website at psrg.org.uk |
| Type Of Material | Technology assay or reagent |
| Provided To Others? | Yes |
| Impact | The various software tools and packages have furthered the research activities of the laboratory since the 1990s and continue to provide key support and drivers for advancing much of current research. These tools and packages are disseminated, on average, to over 100 laboratories per year. |
| URL | http://psrg.org.uk |
| Title | EZ-Rhizo |
| Description | Software for quantitative trait analysis and acquisition for root growth/development |
| Type Of Material | Database/Collection of data |
| Year Produced | 2010 |
| Provided To Others? | Yes |
| Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
| URL | http://psrg.org.uk |
| Title | Henry |
| Description | Software package for electrophysiology and imaging data acquisition and analysis |
| Type Of Material | Data handling & control |
| Provided To Others? | Yes |
| Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
| URL | http://psrg.org.uk |
| Title | OnGuard |
| Description | Quantitative systems biology modelling of cellular transport and homeostasis |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2012 |
| Provided To Others? | Yes |
| Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
| URL | http://psrg.org.uk |
| Description | PBL |
| Organisation | Plant Bioscience Limited Technology |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | IPR on ABA receptor technology and ABA signalling |
| Collaborator Contribution | Funding related to IPR on ABA receptor technology and ABA signalling |
| Impact | Multiple outcomes in publications and industrial contacts |
| Description | PSG |
| Organisation | POSCO - South Korea |
| Country | Korea, Republic of |
| Sector | Private |
| PI Contribution | Base support for meetings and exchange of materials |
| Collaborator Contribution | Base support for meetings and exchange of materials |
| Impact | Base support for meetings and exchange of materials |
| Title | Software tools and packages for electrophysiology and imaging |
| Description | The laboratory continues to develop and refine software/hardware tools for data acquisition and analysis relevant to electrophysiology, single-cell imaging and analysis. These activities are long-standing and open-ended, and develop in line with the current research activities and needs of the laboratory. All software and related packages are made freely available to the research community through the laboratory website at psrg.org.uk |
| Type Of Technology | Software |
| Impact | The various software tools and packages have furthered the research activities of the laboratory since the 1990s and continue to provide key support and drivers for advancing much of current research. These tools and packages are disseminated, on average, to over 100 laboratories per year. |
| URL | http://psrg.org.uk |
| Description | International online services |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | Prof. Blatt and members of his laboratory have contributed to various media events over the years, including online interview contributions (e.g. People behind the Science, a US-based media program) |
| Year(s) Of Engagement Activity | Pre-2006,2006,2008,2011,2015,2016,2017,2018 |
| Description | Invited presentations |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I regularly speak to audiences, from small groups (5-20) to large audiences (>1000) in a variety of settings. In addition to teaching and extramural activities associated with the university, I also speak on invitation to national and international groups a number of times each year and in a variety of settings, academic as well as public. I also reach audiences through short video presentations mounted on the web, these primarily via my laboratory website and the ASPB websites. Anyone reading this entry is welcome to visit these sites to learn more. The impacts arising from my presentations are varied. For example, a common consequence of my speaking in academic settings is to attract potential researchers to visit my laboratory and, frequently, to interest potential collaborators and students/postdocs to my research group. At scientific meetings, my talks often attract interest also from researchers interested in the various tools and materials that my research has produced, including the various vector systems and software packages that I |
| Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
| URL | http://psrg.org.uk |
| Description | Schools and displays |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | Yes |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | As these were multiple events, this question is not informative or useful. Participants varied from numbers in the tens to several thousands Extensive training of participating laboratory members as well as broad scope reach to schools and communities, in the case of the GCC science days to the west of Scotland and in the case of the IFPD activities to audiences within and outside the UK |
| Year(s) Of Engagement Activity | 2010,2011,2012,2013,2014,2015,2016,2017,2018 |
| URL | http://psrg.org.uk |
| Description | Teaching Tools |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | Yes |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | The PI has supported the editor in developing these tools since their inception in 2009 and has contributed to recent tools relating to membranes and transport education The Tool received an international award in 2010 for excellence in education and has an acknowledged takeup worldwide in over 3000 institutions |
| Year(s) Of Engagement Activity | 2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
| URL | http://psrg.org.uk |
| Description | Teaching Tools |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | Yes |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | The PI has supported the editor in developing these tools since their inception in 2009 and has contributed to recent tools relating to membranes and transport education The Tool received an international award in 2010 for excellence in education and has an acknowledged takeup worldwide in over 3000 institutions |
| Year(s) Of Engagement Activity | 2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
| URL | http://psrg.org.uk |