Mitotic Spindle Organizing Protein 1 (MZT1)

MOZART1, MOZART2A (FAM128A), and MOZART2B (FAM128B) copurified with subunits of the gamma-tubulin ring complex (gamma-TuRC), which is essential for spindle assembly and chromosome segregation. When MOZART1 and MOZART2B were used as baits, all 6 gamma-TuRC subunits were identified. MOZART1 and MOZART2B were located on centrosomes throughout the cell cycle and, to a lesser extent, on mitotic spindles of synchronized HeLa cells. Depletion of either MOZART1 or TUBG1 in HeLa cells led to the accumulation of prometaphase cells with monopolar spindles and closely spaced centrosome pairs. Depletion of MOZART1 reduced the association of TUBG1 with centrosomes, suggesting that MOZART1 is required for gamma-TuRC recruitment to centrosomes.