Anomalocaridids

Is the SPB equivalent to the centrosome? Although sharing no structural similarity, the yeast SPB is the functional equivalent of animal cells’ centrosomes. Whereas the centriole-less SPBs are situated in the NE during mitosis (fungi have mostly a closed mitosis) to organize the mitotic spindle, the centrosome, which consists of a pair of cylindrical centrioles surrounded by the pericentriolar material, is associated with the NE in interphase and then becomes released with nuclear envelope breakdown in early mitosis when the centrosome establishes the mitotic spindle. Despite these structural differences, a small set of components of the yeast SPB and the vertebrate centrosome are conserved, reflecting ancestral functions in duplication and MT organization.