Centrosome duplication takes place in –
Correct Answer: S phase
Description: Centrosome duplication is heavily regulated by cell cycle controls. This link between the cell cycle and the centrosome cycle is mediated by cyclin-dependent kinase 2 (Cdk2). There has been ample evidence that Cdk2 is necessary for both DNA replication and centrosome duplication, which are both key events in S phase. It has also been shown that Cdk2 complexes with both cyclin A and cyclin E and this complex is critical for centrosome duplication. Three Cdk2 substrates have been proposed to be responsible for regulation of centriole duplication. These include: nucleophosmin (NPM/B23), CP110, and MPS1. Nucleophosmin is only found in unreplicated centrosomes and it's phosphorylation by Cdk2/cyclin E removes NPM from the centrosomes, initiating procentriole formation. CP110 is an impoant centrosomal protein that is phosphorylated by both mitotic and interphase Cdk/cyclin complexes and is thought to influence centrosome duplication in S phase. MPS1 is a protein kinase that is essential to the spindle assembly checkpoint, and may remodel an SAS6-cored intermediate between severed mother and daughter centrioles into a pair of cawheel protein complexes onto which procentrioles assembleS-phase (synthesis phase) is the pa of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease. Due to the impoance, the regulatory pathways that govern this event in eukaryotes are highly conserved.
Category:
Pathology
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