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Major Discovery in Division Process of Animal Cells

An international group of scientists, led by the University of Granada (UGR) in Spain, has made an unexpected finding about animal cytokinesis, the cellular process that causes the segmentation or division of the cytoplasm to give rise to two daughter cells. This work, which has counted the participation of Canadian researchers and was published on January 6, 2017 in Scientific Reports belonging to Nature Publishing Group, has identified the neuronal apoptosis inhibitory protein (NAIP) throughout cytokinesis. The article is titled “Neuronal Apoptosis Inhibitory Protein (NAIP) Localizes to the Cytokinetic Machinery During Cell Division.” The study basically used microscopic techniques (confocal microscopy and super-resolution microscopy) to show the dynamic of NAIP during the final stages of cell division. The scientists responsible for this study hope that this finding, whose first signs were observed during research that did not address issues about cell division, may lead to other studies that allow a better analysis of the molecular mechanisms that control the final stages of cellular division. As explained by the main author, Francisco Abadía-Molina, Ph.D., from the department of Cellular Biology at the UGR, “Knowing the basic mechanisms that control cell division is fundamental to understand(ing) processes such as development, growth, tissue maintenance, and regeneration, or what are the causes that lead to proliferative pathologies such as cancer, which would allow us to identify new therapeutic targets and strategies."

From a proliferative point of view, every cell in our organism is governed by the cell cycle, which will determine when a cell must divide to give rise to two new daughter cells, or if said cell must remain in a state of non-proliferation. The last stage of the cell cycle is cell division, which comprehends mitosis and cytokinesis. Cytokinesis consists of the segmentation and final partition of the cell that is being divided to give rise to two new cells.

Researchers have now found that, during metaphase, NAIP accumulates at the poles of the mitotic spindle and is seen in the spindle microtubules. At the beginning of the cytokinesis, NAIP is located in the middle spindle, the central area of the mitotic apparatus that defines the plane of cell division. Finally, as the dividing cell pinches apart, the NAIP concentrates in the middle region of the stem body, the last physical connection between the cells that are separating.

This research adds a new function to the already known anti-apoptotic (anti-cellular suicide) properties of NAIP, the first identified member of the anti-apoptotic family (IAPs) in mammals--and also, to the participation of NAIP in the innate immune system, becausee NAIP is a major component of the NLRC4 inflammasome.

[Press release] [Scientific Reports article]