Amorphous no longer: the centrosome comes into focus

Recent genetic and biochemical studies have provided new insights into the molecular basis of centrosome-mediated microtubule nucleation. In addition, molecules and mechanisms involved in microtubule severing and stabilizatio n at the centrosome, assembly of proteins onto centrosomes and regulation o f centrosome duplication and separation are being defined. Characterization of centrosome function, together with studies implicating centrosomes in t umorigenesis and demonstrating that centrosomes are highly organized, are b eginning to bring into focus an organelle once viewed as an 'amorphous clou d'.