Research Identifies Key Component in Cell Division
The Nek9 protein is required for chromosomes to separate into two identical groups
A study by the Institute for Research in Biomedicine (IRB Barcelona) and the Center for Genomic Regulation (acronym in Catalan CRG) highlights the protein Nek9 as a decisive factor in cell division, a fundamental process in both the development of an organism and tissue maintenance.
Headed by the researchers Joan Roig at IRB Barcelona and Isabelle Vernos at the CRG, the study describes how Nek9 is required to divide the chromosome into two identical groups ensuring accurate cell division. In fact, errors in the correct distribution of chromosomes cause many spontaneous miscarriages, some genetic defects such as trisomies, and are also related to the development of tumors.
“Through this study we demonstrate that a fourth family of proteins, namely NIMA and specifically Nek9, exert functions in cell division as important as those undertaken by the widely studied CDK (cdk1), Polo (Plk1) and Aurora (Aurora A and B) kinases,” explains Joan Roig, specialist on the NIMA protein family and co-discoverer of Nek9.
The scientists specialise in the first stages of mitosis which is the process by which the cell nucleus divides in half. Divsion of the chromosomes requires cellular machinery to separate the genetic material into two resulting cells inheriting the same content.
Nek9 participates in the preparation of the centrosomes,
organelles involved in the organization of
mitotic spindle development,
a kind of “rugby ball” made up of microtubules
or “molecular wiring”, which,
together with several “motors” pull and separate
the chromosomes into two identical groups.
Nek9 modifies and controls NEDD1 (discovered in 2006 by Jens Luders a researcher at IRB Barcelona) a molecule involved in the formation of microtubules required to prepare the mitotic spindle.
“Without Nek9 the spindle would not form properly and cell division would be hindered, the cells would die or cause aneuploidies, with unequal distribution of chromosomes, an event that is common in tumors,” explains Isabelle Vernos, an expert in microtubules and cell division.
Interference with cell division is one of the main strategies used against cancer in the pharmaceutical industry, which currently tests new drugs to inhibit Plk1, Aurora and Eg5. Nek9 falls between Plk1 and Eg5, the latter being a motor protein, whose function in mitosis was revealed by Roig in a previous study.
Roig: “We are doing double-edged work: we describe how proteins involved in the initial stages of cell division are related in time and space and in parallel we highlight the possible therapeutic tools, whether markers of disease or anti-mitotic agents, that can stop division and tumour growth.”
Conducted using eggs from the frog Xenopus laevis and human cells, the study is published today in Current Biology, one of the main journals devoted to basic biology.
Nek9 Phosphorylation of NEDD1/GCP-WD Contributes to Plk1 Control of γ-Tubulin Recruitment to the Mitotic Centrosome.
Sdelci S, Schütz M, Pinyol R, Bertran MT, Regué L, Caelles C, Vernos I, Roig J.
Curr Biol. 22, 1-8, August 21, 2012.
Original article: http://www.irbbarcelona.org/index.php/en/news/irb-news/scientific/catalan-researchers-identify-a-key-component-of-cell-division