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Professor Vassilis Koronakis

Projects:

Action of Salmonella effector proteins during mammalian cell entry

Bacterial toxin export and multidrug efflux

Exploiting pathogenic E.coli to model transmembrane receptor signalling

Deciphering cellular signalling to the cytoskeleton

Department of Pathology
University of Cambridge
Tennis Court Road
Cambridge
CB2 1QP

Office Phone: +44 (0)1223 333715

Research Interests

Action of Salmonella effector proteins during mammalian cell entry

Koronakis Research 1Salmonella species continue to cause intestinal disease. Critical to the onset of infection is the ability of the bacteria to enter cells of their mammalian host, from where they replicate and spread. To achieve this, the bacteria deliver a cocktail of effector proteins into the host cell, which subvert signal transduction pathways and stimulate cytoskeletal rearrangements, and trick the normally dormant target cells into engulfing the pathogen. Our goal is to decipher this multifactorial cross-talk between Salmonella effectors and the eukaryotic cellular machinery using a combination of molecular and cellular biology.
Funded by a Wellcome Trust Programme grant, and BBSRC and MRC studentships.

Bacterial toxin export and multidrug efflux

Diverse molecules, from small antibacterial drugs to large protein toxins, are exported directly across both cell membranes of Gram-negative bacteria. This is achieved by the reversible interaction of a two component inner membrane (IM) translocase, which provides substrate specificity and energy, with a protein of the Tolc 'channel-tunnel' family anchored in the outer membrane (OM) that spans the periplasmic space. Having determined the high-resolution structure of TolC, we are using biochemical and biophysical methods in combination with structural biology to probe channel-tunnel dynamics and to identify potential inhibitory agents. In parallel, we are investigating the structure and function of inner membrane translocase components and their interactions with TolC.
Funded by a Wellcome Trust Programme grant (with Professor Colin Hughes)

Exploiting pathogenic E.coli to model transmembrane receptor signalling

Koronakis Research 4Enteropathogenic and enterohaemorrhagic E.coli, which both cause severe diarrhoeal disease, can adhere to mammalian intestinal cells and induce reorganization of the actin cytoskeleton into 'pedestal-like' pseudopods beneath the extracellular bacteria. As pedestal assembly is triggered by E.coli virulence factors that mimic several host cell-signalling components, such as transmembrane receptors, their cognate ligands and cytoplasmic adaptor proteins, it can serve as a powerful model system to study eukaryotic transmembrane signalling. We are exploiting these bacterial factors as versatile tools to probe central cellular signalling pathways.
Funded by an MRC project grant (with Dr Richard Hayward) and a BBSRC studentship

Deciphering cellular signalling to the cytoskeleton

Koronakis Research 5Distinct from ongoing experiments analyzing pathogenesis, we are exploiting effector activities to establish diverse new projects that address complex outstanding questions in cell biology. One such intriguing problem is understanding how cells move. Cells navigate by assembling projections to extend their plasma membrane forward while co-ordinately retracting analogous structures at the opposing edge. We are establishing new techniques to analyze the underlying protein complexes and lipid-mediated signalling using in vitro reconstitution and biomimetic approaches.

  • Research Associates:
    Peter Hume, Daniel Humphreys & Philip Hinchcliffe
  • Graduate Students:
    Andrew Brooks, Anthony Davidson and Qi Hui
  • Chief Research Laboratory Technician:
    Eva Koronakis

Key Publications

  1. WAVE regulatory complex activation by cooperating GTPases Arf and Rac1.
    Koronakis V, Hume PJ, Humphreys D, Liu T, Hørning O, Jensen ON, McGhie EJ.
    Proc Natl Acad Sci U S A. <http://www.ncbi.nlm.nih.gov/pubmed/21844371#> 2011 Aug 30;108(35):14449-54.
  2. Structures of sequential open states in a symmetrical opening transition of the TolC exit duct.
    Pei XY, Hinchliffe P, Symmons MF, Koronakis E, Benz R, Hughes C, Koronakis V.
    Proc Natl Acad Sci U S A. 2011 Feb 1;108(5):2112-7. Epub 2011 Jan 18.
  3. Enteropathogenic Escherichia coli recruits the cellular inositol phosphatase SHIP2 to regulate actin-pedestal formation.
    Smith K, Humphreys D, Hume PJ, Koronakis V.
    Cell Host Microbe. 2010 Jan 21;7(1):13-24.
  4. The Salmonella effector SptP dephosphorylates host AAA+ ATPase VCP to promote development of its intracellular replicative niche.
    Humphreys D, Hume PJ, Koronakis V.
    Cell Host Microbe. 2009 Mar 19;5(3):225-33.
  5. The assembled structure of a complete tripartite bacterial multidrug efflux pump.
    Symmons MF, Bokma E, Koronakis E, Hughes C, Koronakis V.
    Proc Natl Acad Sci U S A. 2009 Apr 28;106(17):7173-8. Epub 2009 Apr 2.
  6. Salmonella takes control: effector-driven manipulation of the host.
    McGhie EJ, Brawn LC, Hume PJ, Humphreys D, Koronakis V.
    Curr Opin Microbiol. 2009 Feb;12(1):117-24. Epub 2009 Jan 20. Review.
  7. Deciphering interplay between Salmonella invasion effectors.
    Cain RJ, Hayward RD, Koronakis V.
    PLoS Pathog. 2008 Apr 4;4(4):e1000037.
  8. Salmonella SPI1 effector SipA persists after entry and cooperates with a SPI2 effector to regulate phagosome maturation and intracellular replication.
    Brawn LC, Hayward RD, Koronakis V.
    Cell Host Microbe. 2007 Mar 15;1(1):63-75.
  9. Phosphorylation of the enteropathogenic E. coli receptor by the Src-family kinase c-Fyn triggers actin pedestal formation.
    Phillips N, Hayward RD, Koronakis V.
    Nat Cell Biol. 2004 Jul;6(7):618-25. Epub 2004 Jun 27.
  10. Control of actin turnover by a salmonella invasion protein.
    McGhie EJ, Hayward RD, Koronakis V.
    Mol Cell. 2004 Feb 27;13(4):497-510.