5w4f

Structural highlights

Function

[IMA1_MOUSE] Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. [DPOLM_HUMAN] Gap-filling polymerase involved in repair of DNA double-strand breaks by non-homologous end joining (NHEJ). Participates in immunoglobulin (Ig) light chain gene rearrangement in V(D)J recombination.^{[1] [2] [3] [4]}

References

1. ↑ Nick McElhinny SA, Ramsden DA. Polymerase mu is a DNA-directed DNA/RNA polymerase. Mol Cell Biol. 2003 Apr;23(7):2309-15. PMID:12640116
2. ↑ Ruiz JF, Juarez R, Garcia-Diaz M, Terrados G, Picher AJ, Gonzalez-Barrera S, Fernandez de Henestrosa AR, Blanco L. Lack of sugar discrimination by human Pol mu requires a single glycine residue. Nucleic Acids Res. 2003 Aug 1;31(15):4441-9. PMID:12888504
3. ↑ Capp JP, Boudsocq F, Besnard AG, Lopez BS, Cazaux C, Hoffmann JS, Canitrot Y. Involvement of DNA polymerase mu in the repair of a specific subset of DNA double-strand breaks in mammalian cells. Nucleic Acids Res. 2007;35(11):3551-60. Epub 2007 May 5. PMID:17483519 doi:http://dx.doi.org/10.1093/nar/gkm243
4. ↑ DeRose EF, Clarkson MW, Gilmore SA, Galban CJ, Tripathy A, Havener JM, Mueller GA, Ramsden DA, London RE, Lee AL. Solution structure of polymerase mu's BRCT Domain reveals an element essential for its role in nonhomologous end joining. Biochemistry. 2007 Oct 30;46(43):12100-10. Epub 2007 Oct 4. PMID:17915942 doi:10.1021/bi7007728