PromoKolleg Cell Division:Nuclear processes during the cell cycle
Research in our group focuses on the analysis of nuclear processes during different stages of the cell cycle. We are using both a well-estalished cell free system based on extracts of amphibian eggs and living mammalian cells to analyse the regulation of spindle function in M-phase as well as aspects of the regulation of nuclear integrity in interphase.
The mitotic spindle is a large macromolecular complex consisting of several hundreds of proteins, which contribute to microtubule nucleation and organisation, interaction of microtubules with the chromosomes and regulation of cell cycle progression. In higher eukaryotes, the spindle can only form after breakdown of the nucleus at mitotic onset and activation of nuclear proteins for spindle assembly. The small GTPase Ran plays an essential role in this regulation. We are analysing the function and the regulation of nuclear microtubule-binding proteins using approaches in living cells and in cell free extracts.
In the nucleus of metabolically active cells, proteins sharing common functions are selectively concentrated in subnuclear domains or nuclear bodies. A paradigm therefore is the Cajal body accumulation of the SMN complex, a central component for the maturation of splicing factors, which is also present in the cytoplasm. By the use of biochemical experiments and targeting studies in living mammalian cells, we are analysing modification patterns and regulators of the SMN complex, which define its specific subcellular localisation and function.
Selected publications
Gruss OJ, Nuclear transport receptor goes moonlighting, Nat Cell Biol, 12: 640-41 (2010)
Reber S, Over S, Kronja I and Gruss OJ. CaM kinase II Initiates meiotic spindle depolymerisation independently of APC/C activation, J Cell Biol, 183: 1007-17 (2008)
Tegha-Dunghu J, Neumann B, Reber S, Krause R Erfle H, Walter T, Held M, Rogers P, Hupfeld K, Ruppert T, Ellenberg, J and Gruss OJ Eml3 is a nuclear microtubule binding protein required for proper alignment of
chromosomes in metaphase. J Cell Sci, 121: 1718-26 (2008)
Petri S, Grimmler M, Over S, Fischer U, Gruss OJ. Dephosphorylation of SMN by PPM1G/PP2Cγ governs Cajal
body localization and stability of the SMN complex. J Cell Biol, 179(3): 451-65 (2007)
Gruss OJ and Vernos I, The mechanism of spindle assembly. Functions of Ran and its target TPX2, J Cell Biol,
166: 949-955 (2004)
Gruss OJ, Wittmann M, Yokoyama H, Pepperkok R, Kufer TA, Silljé HHW, Karsenti E, Mattaj IW, Vernos I. Chromosome-induced microtubule assembly mediated by TPX2 is required for spindle formation in HeLa cells,
Nat Cell Biol, 4: 871-9 (2002)
Gruss OJ, Carazo-Salas RE, Schatz CA, Guarguaglini G, Kast J, Wilm M, Le Bot N, Vernos I, Karsenti E, Mattaj IW. Ran induces spindle assembly by reversing the inhibitory effect of importin alpha on TPX2 activity. Cell, 104:
83-93 (2001)
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Research in our group focuses on the analysis of nuclear processes during different stages of the cell cycle. We are using both a well-estalished cell free system based on extracts of amphibian eggs and living mammalian cells to analyse the regulation of spindle function in M-phase as well as aspects of the regulation of nuclear integrity in interphase.
Selected publications
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