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  • Better in the Presence of securina

    images83The known function until Protein securina is to prevent sister chromatids to separate prematurely before they are each anchored properly to spindle microtubules. This function is performed by the securina separate them interacting with the enzyme and inhibiting its proteolytic activity. Once the sister chromatids are properly arranged and anchored in the equatorial plane, the securina is ubiquitin and degraded, releasing to separate them, which then digests the cohesin Scc1. The Scc1 protein digestion results in the destabilization of the protein complex that holds the chromatids and allows their distribution to each of the cell poles. The premature separation of chromosomes can cause an abnormal distribution and occurrence of aneuploidy.


    This paper shows that securina protein is also involved in maintaining genomic stability of the cell, where it undergoes genotoxic damage produced double-strand breaks (DSB) in DNA. Eukaryotic cells repair the DSB by two different mechanisms known as homologous recombination (HR) and nonhomologous end joining (NHEJ). The mechanism NHEJ requires DNA-PK protein complex (DNA-dependent protein kinase), which is the regulatory subunit Ku heterodimer. The securina interacts with Ku, and this interaction disappears when DNA is damaged.


    Of the two cited repair mechanisms in cells lacking securina HR repair mechanism is not affected, however, the mechanism NHEJ is carried out with the same efficiency but poorly, leading to chromosome rearrangements, chromatid breaks resection and abnormal patterns that determine the survival and cell proliferation.

    Published on December 3, 2012 · Filed under: Bioscience, DNA; Tagged as: , ,
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