title: Phosphorylation of Ran-binding protein-1 by Polo-like kinase-1 is required for interaction with Ran and early mitotic progression.
abstract: Polo-like kinase-1 (Plk1) is essential for progression of mitosis and localizes to centrosomes, central spindles, midbody, and kinetochore. Ran, a small GTPase of the Ras superfamily, plays a role in microtubule dynamics and chromosome segregation during mitosis. Although Ran-binding protein-1 (RanBP1) has been reported as a regulator of RanGTPase for its mitotic functions, the action mechanism between Ran and RanBP1 during mitosis is still unknown. Here, we demonstrated in vitro and in vivo phosphorylation of RanBP1 by Plk1 as well as the importance of phosphorylation of RanBP1 in the interaction between Plk1 and Ran during early mitosis. Both phosphorylation-defective and N-terminal deletion mutant constructs of RanBP1 disrupted the interaction with Ran, and depletion of Plk1 also disrupted the formation of a complex between Ran and RanBP1. In addition, the results from both ectopic expression of phosphorylation-defective mutant construct and a functional complementation on RanBP1 deficiency with this mutant indicated that phosphorylation of RanBP1 by Plk1 might be crucial to microtubule nucleation and spindle assembly during mitosis.
authors.affiliation: Laboratory of Cell Cycle and Signal Transduction, World Class University Research Department of Nanobiomedical Science and the Institute of Tissue Regeneration Engineering, Dankook University, 29 Anseo-Dong, Cheonan 330-714, Korea.
authors.forename: Hyo-In
authors.initials: HI
authors.lastname: Hwang
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Ji
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Jang
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000378:metabolism*; D056744:Cyclin B1 / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020931:ran GTP-Binding Protein / Q000378:metabolism*; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D056744:Cyclin B1; D009687:Nuclear Proteins; D010769:Phosphothreonine; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D020931:ran GTP-Binding Protein; D000097869:Polo-Like Kinase 1; C091775:ran-binding protein 1