An improved method for Dictyostelium centrosome isolation.

The Dictyostelium dicoideum centrosome consists of a box-shaped, layered core structure surrounded by dense nodules embedded in amorphous material, which make up the so-called corona. Thus, it differs markedly from centriole-containing centrosomes in animal cells or the plaque structure of yeast spindle pole bodies. For a long time, purification of Dictyostelium centrosomes was hampered by its extraordinarily tight linkage to the nucleus, which resisted all attempts to dissociate centrosomes and nuclei without destruction of the centrosome itself. Fortunately, we were able to solve this problem, and have already published a centrosome isolation protocol that is based on treatment of nucleus/centrosome complexes with sodium pyrophosphate and shear forces, followed by centrosome isolation through sedimentation and filtration techniques. However, isolated centrosomes prepared according to this protocol still contained too many impurities to allow mass spectrometrical analyses. Here, we present an improved protocol for the isolation of Dictyostelium centrosomes that contain considerably less contaminations with cytosolic and nuclear proteins.