Assessing the Role of Ndc80 Kinetochore Complex in Accurate Chromosome Segregation

Abstract

Mitosis is required to grow and develop from a single cell to a multicellular organism. However, this process can often lead to cancer when its regulation is lost. The Highly Express in Cancer 1 (Hec1) protein is one of the four subunits of the Nuclear Division Cycle (Ndc80) complex present in mitosis. The function of this complex is required for robust kinetochore‐microtubule (kMT) attachment and is regulated by Aurora B Kinase phosphorylation of Hec1. Given that Hec1 protein binds directly to spindle microtubules, it certainly plays a critical role in chromosome alignment and segregation. To assess how Hec1 leads to defects in cell division cycle in human cells and induce cancer, we expressed a non‐phosphorylatable version of Hec1 (Hec1‐9A) in MDA‐MB‐436 (breast cancer) cells. We observed how mitosis was modified by the Hec1‐9A mutant by employing immunofluorescence microscopy to mark the chromosomes and the mitotic spindle in our Hec1‐9A positive and control cells. The Hec1‐9A satisfied the genome surveillance mechanism, thus, allowing cells that presented erroneous chromosome alignment and segregation to exit mitosis. Further studies will be aimed to investigate whether spindle checkpoint is defective at erroneous kMT attachments and whether Hec1 plays a role in other steps of mitosis.Support or Funding InformationFunded by NIH‐NIGMS #2R25GM096955Funded by NIH #R00CA178188This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.