Alternative titles; symbols
HGNC Approved Gene Symbol: KIF20B
Cytogenetic location: 10q23.31 Genomic coordinates (GRCh38) : 10:89,701,590-89,774,934 (from NCBI)
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 (see CCNB1; 123836). 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.
By treating bacterial expression libraries with M-phase cytosol containing the relevant kinases, followed by immunoscreening with MPM2 antibody, Westendorf et al. (1994) isolated partial cDNAs encoding MPHOSPH1, which they termed MPP1, and MPHOSPH2, which they termed MPP2 (FOXM1; 602341). Sequence analysis predicted that the partial MPHOSPH1 cDNA encodes a 566-amino acid protein, the first 302 amino acids of which form a coiled-coil alpha helix. The authors determined that the MPM2 antibody-reactive sites of the MPHOSPH proteins consist of 5-amino acid stretches containing a hydrophobic residue, the putative phosphorylated residue (proline), another hydrophobic residue, and finally a basic or hydrophobic residue (e.g., LTPLK).
By immunoblot analysis, Matsumoto-Taniura et al. (1996) showed that when phosphorylated, MPHOSPH1 is expressed as a 220-kD protein in M-phase cells. Immunofluorescence microscopy localized MPHOSPH1 in punctate cytoplasmic foci in both interphase and mitotic cells, with concentrations in centrosomes and mitotic spindles, respectively.
By screening a HeLa cDNA expression library with serum from a scleroderma (181750) patient, followed by RACE and EST database searching, Kamimoto et al. (2001) obtained a full-length cDNA encoding MPHOSPH1, which they termed kinesin-related motor interacting with PIN1 (601052), or KRMP1. Sequence analysis predicted that the 1,780-amino acid KRMP1 protein contains an N-terminal kinesin motor domain with 2 potential nuclear export signals (NESs); a central stalk domain with 2 potential nuclear localization signals (NLSs) and 2 potential NESs; and a C-terminal globular tail domain with 1 NLS. The MPP1 protein identified by Westendorf et al. (1994) is identical to the C-terminal 566 amino acids of KRMP1. Immunoblot analysis showed expression of a 220-kD KRMP1 protein. Functional analysis established that the N-terminal kinesin-related sequence is an innate ATPase. In addition, the N-terminal head domain is relatively weakly phosphorylated by casein kinase II (see 115440), whereas the C-terminal tail domain is strongly phosphorylated by CDC2 kinase (116940). Immunoprecipitation analysis indicated that the approximately 1,000-residue stalk domain contributes to an alpha-helical coiled-coil structure. Confocal microscopy demonstrated localization of KRMP1 in the cytoplasm and nucleolus during interphase. Far Western blot analysis showed binding of the tail domain of KRMP1 to PIN1 through the N-terminal WW domain of PIN1. Flow cytometric analysis determined that cell cycle arrest induced by KRMP1 overexpression could be rescued by the addition of PIN1. Kamimoto et al. (2001) concluded that KRMP1 is a mitotic target regulated by PIN1 and vice versa.
The International Radiation Hybrid Mapping Consortium mapped the MPHOSPH1 gene to chromosome 10 (D10S1571).
Kamimoto, T., Zama, T., Aoki, R., Muro, Y., Hagiwara, M. Identification of a novel kinesin-related protein, KRMP1, as a target for mitotic peptidyl-prolyl isomerase Pin1. J. Biol. Chem. 276: 37520-37528, 2001. [PubMed: 11470801] [Full Text: https://doi.org/10.1074/jbc.M106207200]
Matsumoto-Taniura, N., Pirollet, F., Monroe, R., Gerace, L., Westendorf, J. M. Identification of novel M phase phosphoproteins by expression cloning. Molec. Biol. Cell 7: 1455-1469, 1996. [PubMed: 8885239] [Full Text: https://doi.org/10.1091/mbc.7.9.1455]
Westendorf, J. M., Rao, P. N., Gerace, L. Cloning of cDNAs for M-phase phosphoproteins recognized by the MPM2 monoclonal antibody and determination of the phosphorylated epitope. Proc. Nat. Acad. Sci. 91: 714-718, 1994. [PubMed: 8290587] [Full Text: https://doi.org/10.1073/pnas.91.2.714]