Fig. 2.

a The centrosome serves as central station to mediate substrate and enzyme activities along microtubules towards the minus ends of microtubules driven by dynein (white circles) and toward the plus ends driven by kinesin (black circles). b Through its microtubule-organizing capabilities the centrosome mediates distribution of cell organelles such as mitochondria, Golgi, and vesicles of various sizes, many containing regulatory enzymes for cell cycle regulation