Targeted disruption of Skp2 results in accumulation of cyclin E and p27(Kip1), polyploidy and centrosome overduplication.
The ubiquitin-proteasome pathway plays an important role in control of the abundance of cell cycle regulators. Mice lacking Skp2, an F-box protein and substrate recognition component of an Skp1-Cullin-F-box protein (SCF) ubiquitin ligase, were generated. Although Skp2(-/-) animals are viable, cells in the mutant mice contain markedly enlarged nuclei with polyploidy and multiple centrosomes, and show a reduced growth rate and increased apoptosis. Skp2(-/-) cells also exhibit increased accumulation of both cyclin E and p27(Kip1). The elimination of cyclin E during S and G(2) phases is impaired in Skp2(-/-) cells, resulting in loss of cyclin E periodicity. Biochemical studies showed that Skp2 interacts specifically with cyclin E and thereby promotes its ubiquitylation and degradation both in vivo and in vitro. These results suggest that specific degradation of cyclin E and p27(Kip1) is mediated by the SCF(Skp2) ubiquitin ligase complex, and that Skp2 may control chromosome replication and centrosome duplication by determining the abundance of cell cycle regulators.
Nakayama
K
K
Laboratory of Embryonic and Genetic Engineering, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Nagahama
H
H
Minamishima
Y A
YA
Matsumoto
M
M
Nakamichi
I
I
Kitagawa
K
K
Shirane
M
M
Tsunematsu
R
R
Tsukiyama
T
T
Ishida
N
N
Kitagawa
M
M
Nakayama
K
K
Hatakeyama
S
S
D000818:Animals; D017209:Apoptosis; D042846:CDC2-CDC28 Kinases; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D048429:Cell Size; D002478:Cells, Cultured; D018385:Centrosome / Q000378:metabolism*; D044842:Cullin Proteins; D019927:Cyclin E / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D017353:Gene Deletion; D015801:Helminth Proteins / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010507:Periodicity; D011123:Polyploidy; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D044786:S-Phase Kinase-Associated Proteins; D044843:SKP Cullin F-Box Protein Ligases; D013601:T-Lymphocytes / Q000166:cytology; D025521:Tumor Suppressor Proteins; D014452:Ubiquitins / Q000378:metabolism
C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; C503646:Cul3 protein, mouse; C100318:Cullin 1; D044842:Cullin Proteins; D019927:Cyclin E; D015801:Helminth Proteins; D008869:Microtubule-Associated Proteins; D044786:S-Phase Kinase-Associated Proteins; D025521:Tumor Suppressor Proteins; D014452:Ubiquitins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D044843:SKP Cullin F-Box Protein Ligases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D010453:Peptide Synthases