This work would not have been possible without Emine Ali, my co-first author and resident Tetrahymena expert, and co-authors @lauraelse.bsky.social , Harmjan, Paula, and of course my supervisors @eelcotromer.bsky.social, Berend Snel and @kopslab.bsky.social. Thanks to all! (11/11)

All in all, we find that T. thermophila has a unique kinetochore combining both highly-divergent, but ancient, as well as more recently-evolved components into a functional whole. (10/11)

Finally, we identified one unconventional component to be a highly-divergent member of the kinesin-6 family. So far, no kinesin-6 family member has been reported at the kinetochore in model organisms, but its presence in T. thermophila may suggest an ancestral function here. (9/11)

We find three unconventional components localising to the inner kinetochore, a known hub for evolutionary novelty. Our homology searches revealed that they have very diverse origins despite likely co-orchestrating the various functions of the inner kinetochore. (8/11)

To uncover how the different components assemble in the T. thermophila kinetochore, we performed nanometer-scale intra-kinetochore measurements. This revealed that the T. thermophila kinetochore assembles much like the human kinetochore despite high levels of divergence. (7/11)

There were also proteins without homology to known kinetochore components. Further searches revealed that they have a wide range of evolutionary backgrounds, some neofunctionalised, others arose through lineage-specific gene birth and yet others may be unrecognised ancestral kinetochore units.(6/11)

Surprisingly, we found no orthologs of either the Dam1 nor the Ska complexes, and also a large number of spindle assembly checkpoint proteins remained elusive. (5/11)

Using deep-homology searches with sequence-based methods as well as AlphaFold-based structural searches, we found a set of highly-diverse orthologs of known kinetochore components. Combined, these constitute a primary axis of the kinetochore: CENP-C, the MIS12 complex and the NDC80 complex. (4/11)

By performing proximity-labeling proteomics combined with microscopy on the few known kinetochore components in the classic model organism T. thermophila, we uncovered a range of proteins associated to its kinetochore, but it was unclear what the evolutionary origins of these proteins were. (3/11)

The kinetochore composition of ciliates has long been elusive, as they seemed to lack many known components. Moreover, they have a unique cell division process, as are binucleated but only one undergoes mitosis. We wanted to find out how they segregate their chromosomes during cell division. (2/11)