Research

Summary

Lipid membranes are barriers separating the cell from the extracellular environment and organizing the inside of the cell into biochemically distinct compartments in which specific cellular functions are performed. Crossing of these membranes by proteins is fundamental for normal cell function. Pathogens have also developed mechanisms to cross the cell protective membrane barrier. Macromolecular machines are often driving the passage of cellular or pathogenic proteins through membranes.

Our research focuses on understanding the mechanisms used by proteins to cross cellular membranes. We are studying several biological systems: polyomavirus, anthrax toxins and ERAD. We use use a multidisciplinary approach combining biochemical and structural biology techniques (cryo-electron microscopy and tomography).

Anthrax toxins

With the threat of emerging and re-emerging infectious diseases, combined with potential risk of terrorist attacks, there is an urgent need to examine the initial steps of infection (entry into the host cell). We use anthrax toxins as a model system to study how bacteria inject toxins into the host cell. In particular, we are investigating how the two anthrax toxic factors, LF and EF, interact with the pore forming moiety PA, how PA inserts into the cell membrane and enables the entry of LF and EF into the cell.

The role of the AAA ATPase in ERAD

Abnormal (or short-lived) proteins in the ER are selectively transported back across the ER membrane to the cytosol for degradation by the proteasome (ERAD). Malfunction of this process, which can be caused by aging, genetic mutations, or environmental factors, result in various diseases such as diabetes, inflammation, and neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, Paget's disease (the second most common bone disease) and bipolar disorder. The AAA ATPase p97 plays a central role in ERAD but its exact mechanism of action is not known. We are investigating its function by studying its interactions with other important players of the ERAD pathway such as the ER membrane proteins Derlin-1 and VIMP, the p97-co-factor Ufd1–Npl4 and substrates.

Polyomavirus

Cell entry of non-enveloped viruses is poorly understood. To understand how polyomavirus enter the cell, we are studying a possible conformational change the capsid undergoes before cell entry.

COPI

Other collaborative projects

We have also several other collaborative projects underway. These projects are done in collaboration with established investigators in Canada, USA and France.

Funding

Research in the lab is funded by:
McGill Start-up fund
The Canadian Institutes of Health Research (CIHR)
The Natural Sciences and Engineering Research Council of Canada (NSERC)                                                                                                                                                 The Canada Foundation for Innovation

Recent publications

1- Feresteh Karimzadeh, Martin Primeau, Driss Mountassif, Isabelle Rouiller, and Nathalie
Lamarche-Vane. A stretch of polybasic residues mediates Cdc42 GTPase-activating protein (CdGAP) binding to phosphatidylinositol-3,4,5 triphosphate and regulates its GAP activity. J Biol Chem. 2012 Apr 19. [Epub ahead of print]                                                                                                                                                     2- Laleh Alisaraie, Isabelle Rouiller (2012). Full-Length Structural Model of RET3 and SEC21: Identification of Binding Sites on Appendage for Accessory Protein Recruitment Motifs. Journal of molecular modeling. J Mol Model. 2012 Jan 14. [Epub ahead of print]                                                                                                 3- Gopakumar Gopalakrishnan, Patricia T. Yam, Carolin Madwar, Mihnea Bostina, Isabelle Rouiller, David R. Colman, and R. Bruce Lennox. Label-Free Visualization of Ultrastructural Features of Artificial Synapses via Cryo-EM. ACS Chem. Neurosci. 2011, 2, 700−704. Highlighted in  ACS Chem. Neurosci. 2011, 2, 684−684.                 4- Xiao-Ping Xu, Isabelle Rouiller, Brian D Slaughter, Coumaran Egile, Eldar Kim, Jay R Unruh, Xiaoxue Fan, Thomas D Pollard, Rong Li, Dorit Hanein and Niels Volkmann. Three-dimensional reconstructions of Arp2/3 complex with bound nucleation promoting factors. EMBO J. 2011, 31(1):236-47                                              5- Tong Zhang, Bama Dayanandan, Isabelle Rouiller, Elizabeth J. Lawrence, Craig A. Mandato Growth-arrest-specific protein 2 inhibits cell division in Xenopus embryos. PLoS One. 2011;6(9):e24698.                               6- Wenjun Song, Jin Chen, Alejandra Petrilli, Geraldine Liot, Eva Klinglmayr, Yue Zhou,Patrick Poquiz, Jonathan Tjong, Mahmoud A. Pouladi, Michael R. Hayden, Eliezer Masliah, Mark Ellisman, Isabelle Rouiller, Robert Schwarzenbacher, Blaise Bossy, Guy Perkins, Ella Bossy-Wetzel. Mutant Huntingtin intereacts with the mitochondrial fission GTPase Drp1, increases its enzymatic activity, and mediates neuronal injury. Nature Med. 2011 Mar;17(3):377-82.                                                                                                                           7- Pierre Karam , An Ngo , Isabelle Rouiller , Gonzalo Cosa. Unraveling Electronic Energy Transfer in Single Conjugated Polyelectrolytes Encapsulated in Lipid Vesicles. Proc Natl Acad Sci U S A. 2010 Oct 107(41):17480-5.  8- Meghan E. Byrne, David A. Ball, Jean-Luc Guerquin-Kern, Isabelle Rouiller, Ting-Di Wu, Kenneth H. Downing, Hojatollah Vali,  Arash Komeili. Desulfovibrio magneticus RS-1 contains an iron and phosphorus-rich organelle distinct from its bullet-shaped magnetosomes. Proc Natl Acad Sci U S A. 2010 Jul 6;107(27):12263-8.             9- Gopakumar Gopalakrishnan, Peter Thostrup, Isabelle Rouiller, Anna Lisa Lucido, David R. Colman and R. Bruce Lennox. Lipid Bilayer Membrane Triggered Presynaptic Vesicle Assembly. ACS Chem. Neurosci. (2010), 1, 86–94.                                                                                                                                                 10- Shaoyong Yu, Tony Azzam, Isabelle Rouiller, and Adi Eisenberg. "Breathing" vesicles (2009). J. Am. Chem. Soc. 131 (30), pp 10557–10566. Highlighted in Nature. 2009 Sep 3;461(7260):45-7.                                     11- Hua Yang, Christopher K. McLaughlin, Faisal A. Aldaye, Andrzej Z. Rys, Graham D. Hamblin, Isabelle Rouiller, and Hanadi F. Sleiman. (2009) Metal-Nucleic Acid Cages. Nature Chemistry 1: 390–396                                12- Dalia Halawani, Andréa LeBlanc, Isabelle Rouiller, Stephen Michnick, Marc Servant and Martin Latterich. (2009) Hereditary inclusion body myopathy-linked p97/VCP mutations in the NH2-domain and the D1 ring modulate p97/VCP ATPase activity and D2 AAA+ ring conformation. Mol Cell Biol.  29(16):4484-94                  13- Gopakumar Gopalakrishnan, Isabelle Rouiller, David R. Colman, and R. Bruce Lennox (2009) Supported Bilayers of Different Lipids on Spherical Silica Substrates. Langmuir 25(10):5455-8.                                        14- Jafar Kafaie, Marjan Dolatshahi, Lara Ajamian, Rujun Song, Andrew J Mouland, Isabelle Rouiller, Michael Laughrea (2009). Role of capsid sequence and immature nucleocapsid protein in Human Immunodeficiency. Virology 385(1):233-44.                                                                                                                        15- Dirk Schumann, Timothy D. Raub, Robert E. Kopp, Jean-Luc Guerquin-Kern, Ting-Di Wu, Isabelle Rouiller, Aleksey V. Smirnov, S. Kelly Sears, Uwe Lücken, Sonia M. Tikoo, Reinhard Hesse,  Joseph L. Kirschvink, & Hojatollah Vali (2008). Gigantism in Unique Biogenic Magnetite at the Paleocene-Eocene Thermal Maximum.  Proc. Natl. Acad. Sci. A105(46):17648-53.                                                                                                 16- Isabelle Rouiller, Xu Xiao-Ping, Amann Kurt J., Egile Coumaran, Nickell Stephan, Nicastro Daniela, Li Rong, Pollard Thomas D., Volkmann Niels , and Hanein Dorit (2008). The structural basis of actin filament branching by the Arp2/3 complex J. Cell Biol. 180(5):887-95.

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