Dr. Stefano Maffini
Projektgruppenleiter, Mechanistische Zellbiologie
To successfully complete cell division, somatic eukaryotic cells must coordinate a number of processes whose ultimate goal is to produce a progeny with an identical genetic content. To achieve such a difficult task, dividing cells assemble the mitotic spindle, an organised network of dynamic microtubules that attaches to the chromosomes to allow for their movement. Central to the mitotic process, is the kinetochore, a multi-subunit protein complex that assembles on centromeric chromatin of mitotic chromosomes. By attaching to the spindle’s microtubules, kinetochores harness the force generated by dynamic microtubules tips to promote chromosome movement. The fidelity of mitosis is safeguarded by the Spindle Assembly Checkpoint (SAC), a signal transduction pathway ensuring 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 activates the SAC to prevent segregation error and activates error-correction mechanisms that disrupt faulty attachments and promote the formation of new, correct ones.
To summarise this molecular context, the main functions of the kinetochores are to provide for 1) MT attachment, 2) the correction of erroneous attachments and 3) a catalytic platform from which the SAC operates. Despite being studied for many decades, the key molecular aspects that define these processes have not been understood yet and many outstanding questions remain unanswered. How is the KT assembled? How does the KT function as a catalytic platform that ensures appropriate SAC signalling and chromosomes movement?
To understand the molecular details governing these cellular processes we employ a multidisciplinary approach that includes cell biology, microscopy, biochemistry and structural biology.
Our main goals include:
1) understanding the cell biology of kinetochore assembly and its functional organisation
2) dissect the molecular mechanism controlling the SAC
3) develop cell biology technology and methodology as a tool to achieve the above mentioned points.
To do so, we take advantage of a number of microscopy techniques, such as live imaging, FRAP, Photoactivation, TIRF and FRET/FLIM.
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
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
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
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. doi: 10.7554/eLife.02978.
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. doi: 10.1083/jcb.201205119.
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. doi: 10.1038/ncb2423.
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. doi: 10.1016/j.cub.2009.07.059.