title: Nuclear localization of the cell cycle regulator CDH1 and its regulation by phosphorylation.
abstract: The anaphase-promoting complex activated by CDC20 and CDH1 is a major ubiquitination system that controls the destruction of cell cycle regulators. Exactly how ubiquitination is regulated in time and space is incompletely understood. Here we report on the cell cycle-dependent localization of CDH1 and its regulation by phosphorylation. CDH1 localizes dynamically to the nucleus during interphase and to the centrosome during metaphase and anaphase. The nuclear accumulation of CDH1 correlates with a reduction in the steady-state amount of cyclin A, but not of cyclin E. A nuclear localization signal conserved in various species was identified in CDH1, and it sufficiently targets green fluorescent protein to the nucleus. Interestingly, a CDH1-4D mutant mimicking the hyperphosphorylated form was constitutively found in the cytoplasm. In further support of the notion that phosphorylation inhibits nuclear import, the nuclear localization signal of CDH1 with two phospho-accepting serine/threonine residues changed into aspartates was unable to drive heterologous protein into the nucleus. On the other hand, abolition of the cyclin-binding ability of CDH1 has no influence on its nuclear localization. Taken together, our findings document the phosphorylation-dependent localization of CDH1 in vertebrate cells.
authors.affiliation: Institute of Molecular Biology and the Department of Biochemistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Yick-Pang
authors.initials: YP
authors.lastname: Ching
authors.forename: Abel C S
authors.initials: AC
authors.lastname: Chun
authors.forename: Dong-Yan
authors.initials: DY
authors.lastname: Jin
mesh_terms: D000595:Amino Acid Sequence; D000705:Anaphase / Q000502:physiology; D064200:Cdh1 Proteins; D002467:Cell Nucleus / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism; D019925:Cyclin A / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007399:Interphase / Q000502:physiology; D008677:Metaphase / Q000502:physiology; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000378:metabolism*; D010766:Phosphorylation; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C577583:CDH1 protein, S cerevisiae; D064200:Cdh1 Proteins; D019925:Cyclin A; D019927:Cyclin E; D019913:Nuclear Localization Signals; D029701:Saccharomyces cerevisiae Proteins