A Cdc2-sensitive interaction of the UbL domain of XDRP1S with cyclin B mediates the degradation of cyclin B in Xenopus egg extracts.
The yeast UbL-UBA protein Dsk2 is thought to act as a shuttle protein that delivers polyubiquitinated proteins to the proteasome. Previously, we identified Xenopus Dsk2-related protein, XDRP1, as a cyclin A-interacting protein. Using Xenopus egg extracts, we further characterized its two isoforms, XDRP1L and XDRP1S, with respect to cyclin binding and its degradation. Polyubiquitinated cyclins bound to the UBA domain of XDRP1L and XDRP1S, whereas monomeric cyclins A and B bound to the UbL domain of XDRP1S but not to XDRP1L. Binding of XDRP1S with monomeric cyclins was affected by a Cdc2-mediated phosphorylation of either the XDRP1S UbL domain or cyclins. Degradation of cyclin B was also prevented by XDRP1S in a Cdc2-sensitive manner. Loss of the XDRP1S-cyclin interaction allowed cyclins to be degraded in calcium-treated CSF extracts. These results suggest that the shuttling pathway via the UbL-UBA protein XDRP1 participates in degradation of mitotic cyclins in Xenopus eggs.
Tanaka
Kanae
K
Department of Molecular Biology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
Funakoshi
Minoru
M
Kobayashi
Hideki
H
D000818:Animals; D001665:Binding Sites; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002457:Cell Extracts / Q000737:chemistry; D002478:Cells, Cultured; D019926:Cyclin B / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis
D002457:Cell Extracts; D019926:Cyclin B; D009687:Nuclear Proteins; D010750:Phosphoproteins; D029867:Xenopus Proteins; C122049:DAPK2 protein, Xenopus; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D003546:Cysteine Endopeptidases; C118083:Ulp1 protease