Diagram of the Centrosome Cycle Large Coffee Mug

Centrosomes are the major microtubule organising centre (MTOC) in mammalian cells. Failure of centrosome regulation can cause mistakes in chromosome segregation and is associated with aneuploidy. A centrosome is composed of two orthogonal cylindrical proteins, called centrioles, which are surrounded by an electron dense and protein dense amorphous cloud of pericentriolar matrix, often abbreviated as "PCM". The PCM is essential for nucleation and organisation of microtubules. The centrosome cycle is important to ensure that daughter cells receive a centrosome after cell division. As the cell cycle progresses, the centrosome undergoes a series of morphological and functional changes. Initiation of the centrosome cycle occurs early in the cell cycle, so that by the time mitosis occurs there are two centrosomes.