Dr. Stefano Maffini

Dr. Stefano Maffini

Project Group Leader, Mechanistic Cell Biology

 


Research Focus

The purpose of cell division is to generate two genetically identical daughter cells. To successfully complete this process, also called mitosis, somatic eukaryotic cells must coordinate, both in time and space, the activity of several cellular components. To perform such a difficult task, dividing cells assemble the mitotic spindle, an organized network of dynamic microtubules that attaches to the chromosomes to allow for their movement and, ultimately, their timely and safe segregation into the newly formed cells. Central to the mitotic process is the kinetochore, a multi-subunit protein complex that assembles on centromeres, a specific region of mitotic chromosomes. By attaching to the spindle’s microtubules, kinetochores harness the force generated by dynamic microtubules tips and promote directional chromosome movement in a controlled manner. The fidelity of mitosis is safeguarded by the Spindle Assembly Checkpoint (SAC), a signal transduction pathway that ensures that mitotic chromosomes will not separate until they are all properly attached to microtubules emanating from opposite poles of the spindle. Unattached kinetochores are the signal that activate the SAC to prevent segregation error and, when required, enable an error-correction mechanism that disrupt faulty attachments and promote the formation of new, correct ones.

In this molecular context, the main function of the kinetochore is to provide 1) for chromosomes movement by establishing attachment to dynamic microtubules, 2) for the correction of erroneous microtubules attachments that are not suitable for safe and timely segregation and 3) a catalytic platform from which the SAC operates. Over the last few decades, our understanding of mitosis has improved significantly, however, the key molecular aspects that define these processes have not been understood yet and many outstanding questions remain unanswered. How does chromosomes assemble the kinetochore? How does kinetochores establish dynamic microtubules attachments able to sustain movement? How does the kinetochore function as a catalytic platform that ensures appropriate SAC signaling?

In light of these questions, our research aims to:

Our main goals include:

1) understand the cell biology of kinetochore assembly and its functional organization.
2) dissect the molecular mechanism controlling the SAC.
3) develop cell biology technologies and methodologies as tools to address fundamental questions in cell biology.

To understand the molecular details governing these cellular processes we employ a multidisciplinary approach that includes the biochemical reconstitutions of fundamental mitotic processes, which are dissected from both a structural and functional standpoint. These observations are then integrated with cell biology experiments aiming at understanding the functional relevance of our biochemical reconstitution efforts. To do so, we take advantage of a number of microscopy techniques, such as fluorescence microscopy, lattice light-sheet live microscopy, FRAP, Photoactivation, TIRF microscopy and FRET/FLIM.

Lattice light microscopy of Cell division

Cell division of human cells, imaged live by lattice light-sheet microscopy. Microtubules from the mitotic spindle (yellow) allow for the duplicated chromosomes (blue) to equally separate between the newly formed daughter cells.


Selected Publications

PubMed Liste>

Piano V, Alex A, Stege P, Maffini S, Stoppiello A, Huis In 't Veld PJ, Vetter I, Musacchio A (2021). CDC20 assists its catalytic incorporation in the mitotic checkpoint complex. Science 
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Burigotto M, Mattivi A, Migliorati D, Magnani G, Valentini C, Roccuzzo M, Offterdinger M, Pizzato M, Schmidt A, Villunger A, Maffini S, Fava LL (2020). Centriolar distal appendages activate the centrosome-PIDDosome-p53 signalling axis via ANKRD26. EMBO Journal 
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Singh P, Pesenti ME, Maffini S, Carmignani S, Hedtfeld M, Petrovic A, Srinivasamani A, Bange T, Musacchio A (2020). BUB1 and CENP-U, Primed by CDK1, Are the Main PLK1 Kinetochore Receptors in Mitosis. Molecular Cell 
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Alex A, Piano V, Polley S, Stuiver M, Voss S, Ciossani G, Overlack K, Voss B, Wohlgemuth S, Petrovic A, Wu Y, Selenko P, Musacchio A, Maffini S (2019). Electroporated recombinant proteins as tools for in vivo functional complementation, imaging, and chemical biology. ELife 
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Pesenti ME, Prumbaum D, Auckland P, Smith CM, Faesen AC, Petrovic A, Erent M, Maffini S, Pentakota S, Weir JR, Lin YC, Raunser S, McAinsh AD, Musacchio A (2018). Reconstitution of a 26-Subunit Human Kinetochore Reveals Cooperative Microtubule Binding by CENP-OPQUR and NDC80. Mol Cell  
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Pentakota S, Zhou K, Smith C, Maffini S, Petrovic A, Morgan GP, Weir JR, Vetter IR, Musacchio A, Luger K (2017). Decoding the centromeric nucleosome through CENP-N.  eLife  
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Overlack K, Bange T, Weissmann F, Faesen AC, Maffini S, Primorac I, Müller F, Peters JM, Musacchio A (2017). BubR1 Promotes Bub3-Dependent APC/C Inhibition during Spindle Assembly Checkpoint Signaling.  Current Biology  
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Mosalaganti S, Keller J, Altenfeld A, Winzker M, Rombaut P, Saur M, Petrovic A, Wehenkel A, Wohlgemuth S, Müller F, Maffini S, Bange T, Herzog F, Waldmann H, Raunser S, Musacchio A (2017). Structure of the RZZ complex and molecular basis of its interaction with Spindly.  Journal of Cell Biology  
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Faesen AC, Thanasoula M, Maffini S, Breit C, Müller F, van Gerwen S, Bange T, Musacchio A (2017). Basis of catalytic assembly of the mitotic checkpoint complex. Nature 
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Overlack K, Primorac I, Vleugel M, Krenn V, Maffini S, Hoffmann I, Kops GJ, Musacchio A (2015). A molecular basis for the differential roles of Bub1 and BubR1 in the spindle assembly checkpoint. eLife 
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Basilico F, Maffini S, Weir JR, Prumbaum D, Rojas AM, Zimniak T, De Antoni A, Jeganathan S, Voss B, van Gerwen S, Krenn V, Massimiliano L, Valencia A, Vetter IR, Herzog F, Raunser S, Pasqualato S & Musacchio A (2014). The pseudo GTPase CENP-M drives human kinetochore assembly. Elife 8:e02978.
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De Antoni A, Maffini S, Knapp S, Musacchio A, Santaguida S (2012). A small-molecule inhibitor of Haspin alters the kinetochore functions of Aurora B. J Cell Biol 199(2):269-84. 
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Logarinho E, Maffini S, Barisic M, Marques A, Toso A, Meraldi P, Maiato H (2012). CLASPs prevent irreversible multipolarity by ensuring spindle-pole resistance to traction forces during chromosome alignment J Cell Biol 14(3):295-303.
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Manning AL, Bakhoum SF, Maffini S, Correia-Melo C, Maiato H, Compton DA (2010).CLASP1, astrin and Kif2b form a molecular switch that regulates kinetochore-microtubule dynamics to promote mitotic progression and fidelity. EMBO Journal 19(18):1566-72.
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Maffini S, Maia AR, Manning AL, Maliga Z, Pereira AL, Junqueira M, Shevchenko A, Hyman A, Yates JR 3rd, Galjart N, Compton DA, Maiato H (2012). Motor-independent targeting of CLASPs to kinetochores by CENP-E promotes microtubule turnover and poleward flux. J Cell Biol 19(18):1566-72.
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