The Cytoskeleton is a fascinating structure of interlinked protein filaments that performs vital roles in cell division, morphogenesis, and transport. Microtubules are prominent members of the cytoskeleton that are characterized by their high stiffness and polarity, which give direction to many cellular processes. We are interested in the mechanisms by which polar microtubules become oriented within microtubule networks such as the mitotic spindle. In the laboratory we use advanced light microscopy to visualize the dynamic construction and maintenance of microtubule networks in fission yeast cells and plant cells. We investigate aspects of microtubule nucleation, microtubule dynamics, and microtubule linkage by molecular motors and bundling proteins. In addition, we devise in vitro reconstitution assays that reproduce some of the complexity of biological systems. By isolating the interactions between specific proteins and microtubules we can study their biochemical and biophysical properties in detail to better understand their role in organizing cellular microtubules. We aim to integrate our observations into quantitative models that describe how order arises out of the seemingly random interactions that microtubules have with each other and their environment.
Selected publications group Janson:
Marcus Braun, Zdenek Lansky, Gero Fink, Felix Ruhnow, Stefan Diez & Marcel E. Janson. Adaptive braking by Ase1 prevents overlapping microtubules from sliding completely apart. Nature Cell Biology 13, 1259-1264 (2011).
L.C. Kapitein, M.E. Janson, S.M. van den Wildenberg, C.C. Hoogenraad, C.F. Schmidt, and E.J. Peterman. Microtubule-driven multimerization recruits ase1p onto overlapping microtubules. Current Biology 18, 1713-1717 (2008).
M.E. Janson, R. Loughlin, I. Loïodice, C. Fu, D. Brunner, F.J. Nédélec and P.T. Tran. Cross-linkers and motors organize dynamic microtubules to form stable bipolar arrays in fission yeast. Cell 128, 357-368 (2007). Featured in: Carazo-Salas, R., and Nurse, P. Sorting out interphase microtubules. Molecular Systems Biology 3:95 (2007); Howard, J., and Tolic-Norrelykke, I.M. Bundling, sliding, and pulling microtubules in cells and in silico. HFSP J 1, 11-14. (2007).
J.W.J. Kerssemakers, E.L. Munteanu, L. Laan, T.L. Noetzel, M.E. Janson, and M. Dogterom. Assembly dynamics of microtubules at molecular resolution. Nature 442, 709-712 (2006).
M.E. Janson, T. Gangi Setty, A. Paoletti and P. T. Tran. Efficient formation of bipolar microtubule bundles requires microtubule-bound γ-tubulin complexes. Journal of Cell Biology 169, 297-308 (2005). Featured in: Becker, B.E., and Cassimeris, L. Cytoskeleton: Microtubules born on the run. Current Biology 15, R551-R554 (2005).
M. Dogterom, J.W.J. Kerssemakers, G. Romet-Lemonne and M. E. Janson. Force generation by dynamic microtubules. Current Opinion in Cell Biology 17, 67-74 (2005).
M.E. Janson and M. Dogterom. A Bending mode analysis for growing microtubules: evidence for a velocity-dependent rigidity. Biophysical Journal 87, 2723-2736 (2004).
M.E. Janson and M. Dogterom. Scaling of microtubule force-velocity curves obtained at different tubulin concentrations. Physical Review Letters 92, 248101 (2004).
M.E. Janson, M.E. de Dood and M. Dogterom. Dynamic instability of microtubules is regulated by force. Journal of Cell Biology 161, 1029-1034 (2003).