Cell Cycle dependent changes in myosin 1 functions
Zusammenfassung der Projektergebnisse
Work during the initial funding phase focused on the detailed functional characterization of Dictyostelium myosin-1B, 1C, 2, 5a, and 5b motor constructs. This work resulted in a much improved basis for the identification of structural features that can serve as reliable indicators of the velocity, tension bearing capacity and regulation of myosin motors. During the second funding phase, work was mostly focused on the characterization of class I myosins. These ubiquous, single-headed myosins are found at the cell periphery, associated with various organelles and in the nucleus. They play important roles in organelle translocation, intracellular transport, and cytoskeleton organization. Although individual class I members are often present in multiple locations at the same time in the cell, there is enough selectivity to exclude non-specific targeting mechanisms. However, the mechanisms of myosin I targeting, which are mainly dictated by the large structural variations within their tail domains has yet to be determined. Using Dictyostelium as a model organism, we identified novel roles of the long-tailed subclass Iα myosins during mitosis and in processes that are associated with nuclear structures. We investigated the cellular functions of vertebrate and Dictyostelium subclass Iα myosins during mitosis and characterized the molecular mechanisms that regulate the spatial and temporal distribution of motor proteins during interphase and mitosis. Myosin-tail/microtubule and myosin-tail/actin interactions were characterized. We made substantial progress in determining the structural factors and functional requirements that underlie the different modes of class I myosins operating at various sub-cellular structures at different stages of the cell cycle. Work performed in the context of Research Unit 629 allowed us to elucidate mechanisms of mechanochemical coupling in high and low duty ratio motors, to obtain insights into a mechanism that governs processivity, dissect the regulatory role of free Mg2+-ions on motor activity and processivity in vitro and in living cells, and to identify and characterize new functions of class-1 myosins in mitosis.
Projektbezogene Publikationen (Auswahl)
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(2006) Functional characterization of the N-terminal region of myosin-2. J Biol Chem 281: 36102-36109
Fujita-Becker S, Tsiavaliaris G, Ohkura R, Shimada T, Manstein DJ, Sutoh K
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(2008). Dictyostelium myosin-5b is a conditional processive motor. J. Biol. Chem., 283, 26902- 26910
Taft, M.H., Hartmann, F.K., Rump, A., Keller H., Chizhov, I., Manstein, D.J., and Tsiavaliaris, G.
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(2008). Mechanism, regulation, and functional properties of Dictyostelium myosin-1B, J. Biol. Chem., 283, 4520-4527
Tsiavaliaris, G., Fujita-Becker, S., Dürrwang, U., Diensthuber, R.P., Geeves, M.A., and Manstein D.J.
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(2009) The mechanism of pentabromopseudilin inhibition of myosin motor activity. Nat Struct Mol Biol 16: 80-88
Fedorov R, Böhl M, Tsiavaliaris G, Hartmann FK, Taft MH, Baruch P, Brenner B, Martin R, Knölker H-J, Gutzeit HO, and Manstein DJ
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(2010) Targeted optimization of a protein nanomachine for operation in biohybrid devices, Angew. Chem. Int. Ed. Engl., 49, 312-316
Amrute-Nayak, M., Diensthuber, R.P., Steffen, W., Kathmann, D., Hartmann, F.K., Fedorov, R., Urbanke, C., Manstein, D.J., Brenner, B., and Tsiavaliaris, G.
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(2010). A myosin IK-Abp1-PakB circuit acts as a switch to regulate phagocytosis efficiency, Mol. Biol. Cell, 21, 1505-1518
Dieckmann, R., von Heyden, Y., Kistler, C., Gopaldass, N., Hausherr, S., Crawley, S.W., Schwarz, E.C., Diensthuber, R.P., Côté; G.P., Tsiavaliaris, G., and Soldati T.
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(2011) Mechanism and specificity of pentachloropseudilin-mediated inhibition of myosin motor activity. J Biol Chem 286, 29700-29708
Chinthalapudi K, Taft MH, Martin R, Heissler SM, Preller M, Hartmann FK, Brandstaetter H, Kendrick- Jones J, Tsiavaliaris G, Gutzeit HO, Fedorov R, Buss F, Knölker H-J, Coluccio LM, and Manstein DJ
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(2011). Myosin-1C associates with microtubules and stabilizes the mitotic spindle during cell division. J. Cell Sci., 124, 2521-2528
Rump, A., Scholz, T., Thiel, C., Hartmann, F. K., Uta, P., Hinrichs, M. H., Taft, M.H. and Tsiavaliaris, G.
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(2013). Global fit analysis of myosin-5b motility reveals thermodynamics of magnesium-sensitive acto-myosin-ADP states. PLoS One, 8(5):e64797
Chizhov, I., Hartmann, F.K., Hundt, N., and Tsiavaliaris, G.
