The replicated genome must be accurately distributed to daughter cells during cell division. Subtle errors in this process lead to birth defects and likely contribute to the genesis of cancer. Severe defects in genome distribution lead to cell lethality and their induction using drugs targeting microtubules, the protein polymers that are a central component of the genome distribution machinery, is a widely used strategy in cancer chemotherapy. A major player in genome distribution during cell division is the kinetochore, a proteinaceous machine built on the centromere regions of mitotic chromosomes to generate a dynamic interface with spindle microtubules. The mechanical properties of kinetochore-microtubule interactions direct chromosome alignment and segregation on the spindle. The mechanics at this interface are tightly integrated with signaling pathways that detect and correct errors in the geometry of chromosome-spindle microtubule attachments and prevent cell cycle progression until all chromosomes are properly connected. These regulatory pathways are central to accurate inheritance of the genome as they ensure that replicated chromosomes are precisely divided into the two daughter cells. The ubiquitously conserved KNL-1/Mis12 complex/Ndc80 complex (KMN) protein network is proposed to play a central role at the kinetochore-microtubule interface. This protein network provides the core microtubule-binding activity of the kinetochore, primarily through a microtubule- binding surface on the 4-subunit Ndc80 complex. The KMN network additionally plays an important role in the spindle checkpoint-the kinetochore-anchored regulatory pathway that generates a """"""""wait anaphase'signal until all of the chromosomes in a cell are correctly attached to the spindle. The proposed work will focus on defining the mechanisms by which the KNL-1 subunit of the KMN network functions as a scaffold coordinating outer kinetochore assembly, microtubule attachment, and checkpoint signaling. The mechanism of microtubule binding by the KMN network and the functional interactions between the two distinct microtubule-binding activities in this protein set, which reside in the Ndc80 complex and in KNL-1, will also be analyzed using a combination of structural and biochemical approaches. In cells, kinetochore-bound spindle microtubules are significantly stabilized. To determine the extent to which the KMN network contributes to this property, the regulation of microtubule polymerization dynamics by the KMN network will be investigated in vitro. The KMN network is closely associated with, and in some cases directly contacts, kinetochore-localized kinases and phosphatases that are implicated in accurate chromosome segregation. The functions of this localized phosphate flux anchored to the KMN network in chromosome segregation and checkpoint signaling will also be addressed.

Public Health Relevance

Errors in distributing the genome during cell division lead to birth defects and contribute to the genesis of cancer. The cellular machinery used for genome distribution is a common target in cancer chemotherapy. This project will focus on understanding the mechanisms that ensure accurate distribution of the genome to daughter cells during cell division. Elucidation of these mechanisms will contribute to our understanding of the development and progression of cancer and provide new avenues for therapeutic development.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Cellular Signaling and Regulatory Systems Study Section (CSRS)
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Deatherage, James F
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Ludwig Institute for Cancer Research Ltd
La Jolla
United States
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Mangal, Sriyash; Sacher, Jennifer; Kim, Taekyung et al. (2018) TPXL-1 activates Aurora A to clear contractile ring components from the polar cortex during cytokinesis. J Cell Biol 217:837-848
Coller, Hilary A; Desai, Arshad (2017) Cell cycle, cell division, and cell death. Mol Biol Cell 28:693-694
Fink, Sarah; Turnbull, Kira; Desai, Arshad et al. (2017) An engineered minimal chromosomal passenger complex reveals a role for INCENP/Sli15 spindle association in chromosome biorientation. J Cell Biol 216:911-923
Lara-Gonzalez, Pablo; Kim, Taekyung; Desai, Arshad (2017) Taming the Beast: Control of APC/CCdc20-Dependent Destruction. Cold Spring Harb Symp Quant Biol 82:111-121
Santaguida, Stefano; Richardson, Amelia; Iyer, Divya Ramalingam et al. (2017) Chromosome Mis-segregation Generates Cell-Cycle-Arrested Cells with Complex Karyotypes that Are Eliminated by the Immune System. Dev Cell 41:638-651.e5
Ohta, Midori; Desai, Arshad; Oegema, Karen (2017) How centrioles acquire the ability to reproduce. Elife 6:
Wang, Shaohe; Tang, Ngang Heok; Lara-Gonzalez, Pablo et al. (2017) A toolkit for GFP-mediated tissue-specific protein degradation in C. elegans. Development 144:2694-2701
Cheerambathur, Dhanya K; Prevo, Bram; Hattersley, Neil et al. (2017) Dephosphorylation of the Ndc80 Tail Stabilizes Kinetochore-Microtubule Attachments via the Ska Complex. Dev Cell 41:424-437.e4
Hattersley, Neil; Desai, Arshad (2017) The nucleoporin MEL-28/ELYS: A PP1 scaffold during M-phase exit. Cell Cycle 16:489-490
Musacchio, Andrea; Desai, Arshad (2017) A Molecular View of Kinetochore Assembly and Function. Biology (Basel) 6:

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