PCM-1, A 228-KD CENTROSOME AUTOANTIGEN WITH A DISTINCT CELL-CYCLE DISTRIBUTION

We report the identification and primary sequence of PCM-1, a 228-kD centrosomal protein that exhibits a distinct cell cycle-dependent association with the centrosome complex. Immunofluorescence microscopy using antibodies against recombinant PCM-1 demonstrated that PCM-1 is tightly associated with the centrosome complex through G(1), S, and a portion of G(2). However, late in G(2), as cells prepare for mitosis, PCM-1 dissociates from the centrosome and then remains dispersed throughout the cell during mitosis before re-associating with the centrosomes in the G(1) phase progeny cells. These results demonstrate that the pericentriolar material is a dynamic substance whose composition can fluctuate during the cell cycle.