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Professor Katalin Torok

Professor of Molecular Neuroscience
To lead internationally recognised research paired with training and teaching excellence

Professor Katalin Török investigates mechanisms that govern and regulate basic biological processes within cells.

She studies cell signalling – how information moves inside and between cells. She investigates the proteins that transmit information along signalling pathways, and how cells respond.

Her research focuses on how components of the calcium signalling pathways function and interact in neurons in processes that are relevant to the formation of memory at the molecular and cellular level.

She develops genetically encoded and chemically derivatised fluorescent protein sensors for real-time monitoring of calcium signalling and glutamate neurotransmission.


Professor Török joined St George's, University of London in 1999 as a Senior Lecturer in Pharmacology and Clinical Pharmacology. She was promoted to Reader in Cell Biology in 2002 and to Professor of Molecular Neuroscience in 2019.

Prior to St George's, she was Lecturer in Biochemistry at Queen Mary and Westfield College (1997 to 1999), Lecturer in Physiology at the University of Newcastle (1995 to 1997) and Lecturer in the Department of Physiology at University College London (UCL) (1993 to 1995).

Professor Török studied for an MSc in Chemistry at Eötvös Lorand University of Sciences, Budapest, Hungary in 1976. She obtained a PhD at Semmelweis University Medical School (SOTE), in the Department of Biochemistry (1981). She was postdoctoral fellow at Boston Biomedical Research Institute in the USA (1981 to 1983), returning to Budapest and SOTE for a year to work as a staff scientist in the Department of Biochemistry.

In 1984 Professor Török joined the Medical Research Council National Institute for Medical Research (NIMR) in Mill Hill, London, where she worked for nine years, first in the Laboratory of Protein Structure and then in the Division of Physical Biochemistry.

Membership of Professional Societies and Committees

Professor Török is a member of the Society for Neuroscience, the Physiological Society, the Biophysical Society, ASBMB and the Biochemical Society.

At St George's, Professor Török is a member of Senate (elected academic member) and of Virtual Panel for PhD examiner approval.

Professor Török is Head of Section of Molecular and Cellular Sciences in the Institute of Neuroscience and Cell Biology

Professional Honours and Recent Invitations

Editorial Board member for NPG Scientific Reports

Invited Speaker: 62nd Annual Meeting, Biophysical Society, New & Notable Symposium, February 2018

Invited speaker: Howard Hughes Medical Institute Janelia Research Campus Conference ‘Fluorescent proteins and Biological Sensors V’ November 2016; ‘Fluorescent proteins and Biological Sensors VI’, October 2018

Invited speaker: 36th Workshop of the Marine Biological Association, Plymouth on Microelectrode Techniques for Cell Physiology, September 2019, September 2021, September 2023

Invited speaker: Paris Neuroscience School, June 2021, May 2022, May 2023, May 2024



Professor Katalin Török investigates mechanisms that govern and regulate basic biological processes within cells.

She studies cell signalling – how information moves inside and between cells. She investigates the proteins that transmit information along signalling pathways, and how cells respond.

Her research focuses on how components of the calcium signalling pathways function and interact in neurons in processes that are relevant to the formation of memory at the molecular and cellular level.

She develops genetically encoded and chemically derivatised fluorescent protein sensors for real-time monitoring of calcium signalling and glutamate neurotransmission.

1) Highly specific and non-invasive imaging of Piezo1-dependent activity across scales using GenEPi.

S. Yaganoglu, K. Kalyviotis, N. Helassa, C. Vagena-Pantoula, D. Jülich, B.M. Gaub, M. Welling, T. Lopes, D. Lachowski, S.S. Tang, A. Del Rio Hernandez, V. Salem, D.J. Müller, S.A. Holley, J. Vermot, J. Shi, K. Török, P. Pantazis. 

Nature Communications 2023 Jul 19;14(1):4352. doi: 10.1038/s41467-023-40134-y.

2) Development and characterisation of novel jGCaMP8f calcium sensor variants with improved kinetics and fluorescence response range.

O. Tran, H.J. Hughes, T. Carter and K.Török.

Frontiers in Cellular Neuroscience (2023) 17:1155406. doi: 10.3389/fncel.2023.1155406

Article collection on 'The Development and Application of Genetically Encoded Sensors for Resolving the Physiology or Pathogenesis in Various Behaviours and Diseases' 

3) Ca2+-dependent and -independent interactions of calmodulin with gap junction cytoplasmic loop peptides.

O. Tran, S. Kerruth, D. Colak, C. Coates, H. Kaur, C. Peracchia, T. Carter and K. Török.

Int J Mol Sci. (2023) 24(4):4153. doi: 10.3390/ijms24044153.

Special Issue on ‘Gap Junction Channels and Hemichannels in Health and Disease’ 

4) Vesicular release probability sets the strength of individual Schaffer collateral synapses.

C.D. Dürst, J.S. Wiegert, C. Schulze, N. Helassa, K. Török and T.G. Oertner.

Nature Communications (2022) 13, 6126.

5) P-selectin mobility undergoes a sol-gel transition as it diffuses from exocytosis sites across the endothelial cell plasma membrane.

N. Hellen, G.I. Mashanov, I.L. Conte, S. le Trionnaire, V. Babich, L. Knipe, A. Mohammed, K. Ogmen, S.M. Almedina, K. Török, M.J. Hannah, J.E. Molloy and T. Carter.

Nature Communications (2022) 13, 3031.

6) Kinetic mechanisms of fast glutamate sensing by fluorescent protein probes.

C. Coates, S. Kerruth, N. Helassa and K. Török.

Biophysical J. (2020) 118, 117-127

7) High-speed imaging of glutamate release with genetically encoded sensors.

C.D. Dürst, J.S. Wiegert, C. Schulze, N. Helassa, S. Kerruth, C. Coates, M. Geeves, K. Török and T.G. Oertner.

Nature Protocols (2019) 14(5):1401-1424. doi: 10.1038/s41596-019-0143-9

8) Single synapse indicators of impaired glutamate clearance derived from fast iGluu imaging of cortical afferents in the striatum of normal and 2 Huntington (Q175) mice.

A. Dvorzhak, N. Helassa, K. Török, D. Schmitz and R. Grantyn.

J. Neuroscience (2019) 39(20):3970-3982. doi:10.1523/JNEUROSCI.2865-18.2019

9) The kinetic mechanisms of fast-decay red-fluorescent genetically-encoded calcium indicators.

S. Kerruth, C. Coates, C.D. Dürst, T.G. Oertner and K. Török.

J. Biological Chemistry (2019) 294(11) 3934 –3946 doi: 10.1074/jbc.RA118.004543

10) Ultrafast glutamate sensors resolve high-frequency release at Schaffer collateral synapses.

N. Helassa, C.D. Dürst, C. Coates, S. Kerruth, U. Arif, C. Schulze, J.S. Wiegert, M. Geeves, T. Oertner and K Török.

Proc. Natl. Acad. Sci. U S A (2018) 115 (21) 5594-5599. doi: 10.1073/pnas.1720648115.

11) High affinity binding of amyloid-beta peptide to calmodulin: structural and functional implications.

I. Corbacho, M. Berrocal, K. Török, A.M. Mata and C. Gutierrez-Merino.

Biochem. Biophys. Res. Comm. 486 (2017) 992-997. doi: 10.1016/j.bbrc.2017.03.151.

12) Design and mechanistic insight into ultrafast calcium indicators for monitoring intracellular calcium dynamics.

N. Helassa, B. Podor, A. Fine and K. Török.

Scientific Reports 6 (2016) 38276; doi: 10.1038/srep38276

13) Fast-response calmodulin-based fluorescent indicators reveal rapid intracellular calcium dynamics.

N. Helassa, X.-h Zhang, I. Conte, J. Scaringi, E. Esposito, J. Bradley, T. Carter, D. Ogden, M. Morad and K. Tӧrӧk.

Scientific Reports 5 (2015) 15978; doi: 10.1038/srep15978

14) Lobe-specific functions of Ca2+.calmodulin in alphaCa2+.calmodulin-dependent protein kinase II activation.

A.M. Jama, J. Gabriel, A.J. Al-Nagar, S.R. Martin, S.Z. Baig, H. Soleymani, Z. Chowdhury, P. Beesley and K. Török.

J. Biological Chemistry 286 (2011) 12308-12316.

15) Time-dependent auto-inactivation of phospho-Thr286-alphaCa2+/calmodulin-dependent protein kinase II.

A.M. Jama, J. Fenton, S.D. Robertson and K. Török.

J. Biological Chemistry 284 (2009) 28146-28155.

16) Calmodulin association with connexin32 derived peptides suggests trans-domain interaction in chemical gating of gap junction channels.

R. Dodd, C. Peracchia, D. Stolady and K. Török.

J. Biological Chemistry 283 (2008) 26911-26920.

17) A two-state model for Ca2+/CaM-dependent protein kinase II (alphaCaMKII) response to persistent Ca2+ stimulation in hippocampal neurones.

P.A.A. Grant, S.L. Best, N. Sanmugalingam, R. Alessio, A.M. Jama, and K. Török.

Cell Calcium 44 (2008) 465-478.

18) PERSPECTIVE: The regulation of nuclear membrane permeability by Ca2+ signaling: A tightly regulated pore or a floodgate?

K. Török.

Science STKE 386 (2007) pe24

19) Role of Ca2+ activation and bilobal structure of calmodulin in nuclear and nucleolar localization.

R. Thorogate and K. Török.

Biochemical J. 402 (2007) 71-80.

20) Endogenously bound calmodulin is essential for the function of the inositol 1,4,5-trisphosphate receptor.

N.N. Kasri, K. Török, A. Galione, G. Callewaert, L. Missiaen, J.B. Parys and H. de Smedt.

J. Biological Chemistry 281 (2006) 8332-8338.

21) Nuclear pore gating by calmodulin.

R. Thorogate and K. Török.

Calcium Binding Proteins 1 (2006) 36-44.

22) The adaptor protein Grb7 is a novel CaM-binding protein: Functional implications of the interaction of calmodulin with Grb7.

H. Li, J. Sanchez-Torres, A.F. del Carpio, A. Nogales-Gonzalez, P. Molina-Ortiz, M.J. Moreno, K. Török and A. Villalobo.

Oncogene 24 (2005) 4206-4219.

23) AlphaCaMKII cellular redistribution in Ca2+ overload.

K. Török, P.A.A. Grant, S.L. Best, R. Alessio.

In Second Messengers and Phosphoprotein Signaling (Medimond) (2005) (M.B. Anand-Srivastava, M. Trembley, A.K. Srivastava, eds) pp. 189-193.

24) Ca2+-dependent and independent mechanisms of calmodulin nuclear translocation.

R. Thorogate and K. Török.

J. Cell Science 117 (2004) 5923-5936.

25) Mechanism of the T286A mutant alpha-Ca2+/calmodulin-dependent protein kinase II interactions with Ca2+/calmodulin and ATP.

A. Tzortzopoulos and K. Török.

Biochemistry 43 (2004) 6404-6414.

26) Ca2+/calmodulin-dependent activation and inactivation mechanisms of alphaCaMKII and Thr286-phospho-alphaCaMKII.

A. Tzortzopoulos, S.L. Best, D. Kalamida and K. Török.

Biochemistry 43 (2004) 6270-6280.

27) A model for the activation of plasma membrane calcium pump isoform 4b by calmodulin.

A.R. Penheiter, Z. Bajzer, A.G. Filoteo, R. Thorogate, K. Török and A.J. Caride.

Biochemistry 42 (2003) 12115-12124.

28) Integration of calcium signals by calmodulin in rat sensory neurones.

J.M. Milikan, T.D. Carter, J.H. Horne, A. Tzortzopoulos, K. Török and S.R. Bolsover.

European J. Neuroscience 15 (2002) 661-70.

29) Calmodulin conformational changes in the activation of protein kinases.

K. Török.

Biochemical Society Transactions 30 (2002) 55-61.

30) Studying the spatial distribution of Ca2+-binding proteins: how does it work for calmodulin.

K. Török, R. Thorogate and S. Howell.

In Methods in Molecular Biology (Humana Press), vol. 173 (2002): Calcium-binding Protein Protocols Vol. 2: Methods and Techniques (H. Vogel ed.) Chapter 29, pp. 383-407.

31) Dual effect of ATP in the activation mechanism of brain Ca2+/calmodulin-dependent protein kinase II by Ca2+/calmodulin.

K. Török, A. Tzortzopoulos, Z. Grabarek, S. L. Best and R. Thorogate.

Biochemistry 40 (2001) 14878-14890.

32) Oligomeric structure of alpha-calmodulin-dependent protein kinase II.

E.P. Morris and K. Török.

J. Molecular Biology 308 (2001) 1-8.

33) Calmodulin regulates the disassembly of cortical F-actin in mast cells but is not required for secretion.

R. Sullivan, M. Burnham, K. Török and A. Koffer.

Cell Calcium 28 (2000) 33-46.

34) Ca2+-calmodulin inhibits Ca2+-release mediated by types 1,2 and 3 inositol trisphosphate receptors.

C.E. Adkins, S.A. Morris, H. De Smedt, I. Sienaert, K. Török, and C.W. Taylor.

Biochemical J. 345 (2000) 357-363.

35) Hormone-induced secretory and nuclear translocation of calmodulin: oscillations of calmodulin concentration with nucleus as an integrator.

T. Takeo, M. Craske, O. Gerasimenko, K. Török, O.H. Petersen and A. Tepikin.

Proc. Natl. Acad. Sci. 96 (1999) 4426-4431.

36) Imaging the spatial dynamics of calmodulin activation during mitosis.

K. Török, M. Wilding, L. Groigno, R.D. Patel and M.J. Whitaker.

Current Biology 8 (1998) 692-699.

37) Inhibition of calmodulin-activated smooth muscle myosin light chain kinase by calmodulin binding peptides and fluorescent (phosphodiesterase-activating) calmodulin derivatives.

K. Török, D.J. Cowley, B.D. Brandmeier, S. Howell, A. Aitken and D.R. Trentham.

Biochemistry 37 (1998) 6188-6198.

38) Connexin 32 of gap junctions contains two cytoplasmic calmodulin binding domains.

K. Török, K. Stauffer and W.H. Evans.

Biochemical J. 326 (1997) 479-483.

39) Activation-dependent and activation-independent localisation of calmodulin to the mitotic apparatus during the first cell cycle of the Lytenichus pictus embryo.

M. Wilding, K. Török and M.J. Whitaker.

Zygote 3 (1995) 219-224.

40) Nuclear calmodulin responds rapidly to calcium influx at the plasmalemma.

F. Zimprich, K. Török and S. Bolsover.

Cell Calcium 17 (1995) 233-238.

41) Mechanism of 2-chloro-(epsilon-amino-Lys75)-(6-(4-N,N-diethylamino-phenyl)-1,3,5-triazin-4-yl)-calmodulin interactions with smooth muscle myosin light chain kinase and derived peptides.

K. Török and D.R. Trentham.

Biochemistry 33 (1994) 12807-12820.

42) Taking a long, hard look at calmodulin's warm embrace.

K. Török and M.J. Whitaker.

Bioessays 16 (1994) 221-224.

43) Location of two contact sites between human smooth muscle caldesmon and Ca2+.calmodulin.

S.B. Marston, I.D.C. Fraser, P.A.J. Huber, K. Pritchard, N.B. Gusev and K. Török.

J. Biological Chemistry 269 (1994) 8134-8139.

44) Flash-photolysis studies of relaxation and cross-bridge detachment – higher sensitivity of tonic than phasic smooth-muscle MgADP.

A. Fuglsang, A. Khromov, K. Török, A.V. Somlyo and A.P. Somlyo.

J. Muscle Research and Cell Motility 14 (1993) 666-677.

45) The effects of MgADP on cross-bridge kinetics: A laser flash photolysis study of guinea-pig smooth muscle.

E. Nishiye, A.V. Somlyo, K. Török and A.P. Somlyo.

J. Physiology 460 (1993) 247-271.

46) Gap junction communication channel - Peptides and anti-peptide antibodies as structural probes.

W.H. Evans, G. Carlile, S. Rahman and K. Török.

Biochemical Society Transactions 20 (1992) 856-861.

47) Effects of calcium binding on the internal dynamic properties of bovine brain calmodulin, studied by NMR and optical spectroscopy.

K. Török, A.N. Lane, S.R. Martin, J.-M. Janot and P.M. Bayley.

Biochemistry 31 (1992) 3452-3462.

48) Inhibition of Ca2+-ATPase by limited proteolysis.

K. Török and N.M. Green.

Progress in Clinical and Biological Research 273 (1988) 165-169.

49) Tryptic cleavage inhibits but does not uncouple Ca2+-ATPase of sarcoplasmic reticulum.

K. Török, B.J. Trinnaman and N.M. Green.

The FEBS Journal 173 (1988) 361-367.

50) Myometrial (Na+ +K+)-activated ATPase and its Ca2+-sensitivity.

A. Turi and K. Török.

Biochimica and Biophysica Acta 818 (1985) 123-131.

51) Gamma-glutamyltransferase in the brain and its role in the formation of gamma-L-glutamyl-taurine.

V. Varga, K. Török, L. Feuer, J. Gulyas and J. Somogyi.

Progress in Clinical and Biological Research 179 (1985) 115-125.

52) Formation of an intramolecular disulphide bond in the mitochondrial adenine nucleotide translocase.

K. Török and S. Joshi.

FEBS Letters 182 (1985) 340-344.

53) Cross-linking of bovine mitochondrial H+-ATPase by copper-o-phenanthroline; interaction of the oligomycin-sensitivity conferring protein with a 24 kD protein.

K. Török and S. Joshi.

The FEBS Journal 153 (1985) 155-159.

54) Resolution and reconstitution of H+-ATPase complex from beef heart mitochondria.

S. Joshi, J.B. Hughes, K. Török and D.R. Sanadi.

Membrane Biochemistry 5 (1985) 309-325.

55) Identification of the 29,000 dalton protein and its relevance to oligomycin-sensitive 32Pi-ATP exchange in bovine heart electron transport particles.

S. Joshi and K. Török.

J. Biological Chemistry 259 (1984) 12742-12748.

56) Isolation of a highly active H+-ATPase from beef heart mitochondria.

J.B. Hughes, S. Joshi, K. Török and D.R. Sanadi.

J. Bioenergetics and Biomembranes 14 (1982) 287-295.

57) Localisation of gamma-glutamyl transpeptidase in neural tissue.

V. Varga, J. Somogyi, K. Langley, M.S. Ghandour, J. Gulyas, K. Török, N. Müllner and P. Mandel.

Advances in Biochemical Pharmacology 3 (1982) 31-38.

58) Formation of gamma-glutamyl-taurine in the rat brain. K. Török, V. Varga, J. Somogyi, L. Feuer and J. Gulyas.

Neuroscience Letters 27 (1981) 145-149.

K. Török and T. Carter: Imaging glutamate in the brain using novel fast fluorescent probes
BBSRC project grant (BB/S003894/1, 1 post-doc, 1 research assistant) 2018-2021. £ 615,802.

K. Török: FastTrack GECI: Development of novel fast calcium indicators for intracellular, extracellular and in vivo imaging
BBSRC project grant (BB/M02556X /1, 1 post-doc, 1 technician) 2015-2018. £ 280,114.

K. Török: Investigation of Ca2+ and calmodulin signalling by novel calmodulin-based fluorescent probes
Wellcome Trust Project grant (094385/Z/10/Z, 1 post-doc) 2011-2015. £ 271,776.

K. Török & D. Ogden (Paris Descartes)
Novel fluorescent calmodulin-based probes for neuroelectrophysiological studies
Royal Society International Joint Project (JP100838) 2011-2013. £ 12,000.

K. Török: The role of nucleotide and protein substrates in the activation mechanism of Ca2+/calmodulin-dependent protein kinase II
Wellcome Trust Project Grant (075931/Z/04/Z, 1 post-doc) 2005-2009. £ 196,618.

K. Török: Real-time measurement of glutamate concentration.
Wellcome Trust Project Grant (060907/Z/00/Z, 1 post-doc) 2000-2004. £ 183,459.

K. TörökFunctions of calmodulin and CaMKII in neuronal calcium signalling.
Supplement to MRC Career Establishment Grant: Equipment, 2000. £ 34,420.

K. TörökFunctions of calmodulin and CaMKII in neuronal calcium signalling.
Medical Research Council Career Establishment Grant (G 9803105, 1 post-doc, 1 research technician/part-time PhD Student, Dr. R. Thorogate) 1999-2004. £ 554,628.

K. TörökMolecular mechanism and signal integrating function of the a neural isoform of calmodulin dependent protein kinase II (aCaMKII).
Wellcome Trust Project Grant (048458/Z/96/A, 1 post-doc) 1996-2002. £ 154,277.

Bolsover and K TörökIntracellular messenger signalling to the nucleus.
Wellcome Trust Project Grant (051903/Z/97/Z) 1997-2000. £ 163,452.

M.J. Whitaker and K. TörökCalcium and calmodulin control of the cell division cycle in cells in culture.
Wellcome Trust project Grant (047059/Z/96/Z) 1996-1997. £ 61,910.

R. Bolsover and K. TörökControl of growth cone by calcium.
Wellcome Trust Project Grant (045051/Z/95/Z) 1995-1997. £ 154,219

M.J. Whitaker and K. TörökThe calcium-calmodulin signalling system at fertilization and during early cycles of sea urchin embryos.
Wellcome Trust Equipment Grant (043014/Z/94/Z) 1994-1997. £ 297,443.

M.J. Whitaker and K. TörökProbes of calmodulin function in living cells.
Wellcome Trust Project Grant 1994-1995. £ 9,740.

Török: Dr. V. Bouryi, Bogomoletz Inst. Of Biophysics, Kiev, Ukraine,
Royal Society Short Visit Grant 2006.

Török‘Calmodulin imaging in neurones'
Royal Society Research Grant 1999. £ 10,000.

Török‘Multifunctional calmodulin kinase'
Royal Society Research Grant 1994. £ 10,000.

Research group

Professor Török works with Research Assistant/Part-time PhD student Holly Hughes  and Research Assistant Oanh Tran.

Former recent research associates:

Dr Silke Kerruth (IC)
Ms Catherine Coates (ICR)
Dr Nordine Helassa (Liverpool University)



Professor Török's collaborators include:

Dr Steven Vogel, NIH/NIAAA Rockville, MD, USA

Professor Rosemarie Grantyn, Charite, Berlin, Germany

Dr Thomas Oertner, Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, Germany

Dr Alan Fine, Dalhousie University, Halifax, Nova Scotia, Canada

Professor Tom Carter, St George’s, University of London, UK

Professor Andrew Plested, Humboldt University Berlin & Cluster of Excellence, Berlin, Germany 

Professor Török teaches students on the MBBS and Biomedical Sciences course as well as on the post-graduate MRes and MSci courses.

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