M-Phase Phosphoprotein 6 (MPHOSPH6)

Progression of cells from interphase to mitosis involves alterations in cell structures and activities. The transition from G2 to M phase is induced by M phase-promoting factor, or MPF. In M phase, many proteins are phosphorylated directly by MPF or indirectly by kinases activated by MPF. These M-phase phosphoproteins (MPPs, or MPHOSPHs) permit disassembly of interphase structures and generation of M-phase enzymatic activities and structures.

Immunoblot analysis showed that when phosphorylated, MPHOSPH6 is expressed as a 17-kD protein in M-phase cells. Immunofluorescence microscopy localized MPHOSPH6 throughout the nucleus, with a modest concentration in nucleoli, in interphase, and throughout the cell in mitotic cells.