Cyclin B1 interacts with the BH3-only protein Bim and mediates its phosphorylation by Cdk1 during mitosis

Fhearraigh, S. Mac; Gee, Margaret M. Mc

doi:10.4161/cc.10.22.18020

Cited by 24 publications

(30 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…BimEL has been shown to form complexes with kinases that phosphorylate it. 19,20,24 Similarly, in Figure 6g we show that that GST-BimEL was able to pull down Aurora A from mitotic extracts derived from HeLa or 293T cells.…”

Section: Resultssupporting

confidence: 60%

“…However, the S94/98A mutant was stabilized at mitosis (compare lanes 7 and 8) and the stabilized form of the protein appeared to migrate slower. Serine 104 of BimEL has been previously shown to be phosphorylated by cdk1 during mitosis, 24 but mutation of this site had no effect on stability (lanes 11 and 12). The S94/98A mutation is clearly still phosphorylated at other sites Figure 2 BimEL is phosphorylated and degraded at mitosis in a mechanism independent of the spindle assembly checkpoint.…”

Section: Resultsmentioning

confidence: 90%

“…Figure 2b (lanes [19][20][21][22][23][24][25][26][27] show that taxol treatment stabilized the APC/C substrates, cyclin B and securin, but did not affect stability of BimEL or Wee1, suggesting that degradation of BimEL was APC/C independent. Interestingly, treatment with RO3306 stabilized BimEL (compare lanes 1-9 with lanes 28-36 of Figure 2b), suggesting that cdk1 activity was required for degradation.…”

Section: Resultsmentioning

confidence: 99%

“…P-H3 is included as a marker for onset of mitosis and APC2 as loading control in mitosis as the mutated protein migrates slower in mitosis and may be due to phosphorylation by cdk1 as previously reported. 24,25 We further mutated four other potential cdk phosphorylation sites on BimEL but none displayed major effects on mitotic stability of the protein. These data indicate that BimEL is actively ubiquitinated and targeted for degradation during mitosis using a mechanism that requires phosphorylation at S93/94/98.…”

Section: Resultsmentioning

confidence: 99%

“…Early reports suggested that this phosphorylation is catalyzed by ERK1/2 21 and ERK5 22 most likely as a pro-survival signal. However, more recent studies have found that mitotic phosphorylation of BimEL is not dependent on ERK1/2 or ERK5 signaling; 23 but rather upon cyclin-dependent kinase 1 (CDK1) activity 24,25 and is associated with the polyubiquitination and proteasome-dependent turnover of BimEL. 25 Although there is now considerable evidence that Bim levels are regulated by phosphorylation and proteasomemediated proteolysis during mitosis, the mechanism remains unknown.…”

mentioning

confidence: 99%

See 4 more Smart Citations

BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

et al. 2013

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

et al. 2013

View full text Add to dashboard Cite

Prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim reduces the association of Bcl-2 with Bak or Bim, provoking Bak activation and mitochondrial apoptosis in nocodazole-treated Jurkat T cells

et al. 2013

View full text Add to dashboard Cite

Treatment of Jurkat T cells with the microtubule-depolymerizing agent nocodazole (NOC) caused prometaphase arrest and apoptosis. NOC-induced mitochondrial apoptotic events including Bak activation, Δψm loss, cytochrome c release, and caspase cascade activation were blocked by Bcl-2 overexpression. However, mitotic arrest, Cdc25C activation, upregulation of cyclin B1 levels, Cdk1 activation, Bcl-2 phosphorylation at Thr-56 and Ser-70, and Bim phosphorylation were retained. The treatment of Jurkat T cells concomitantly with NOC and the G1/S-blocking agent hydroxyurea resulted in G1/S arrest and complete abrogation of all apoptotic events. The association of Bcl-2 with Bim or Bak declined after the prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim, whereas the association of Bcl-2 with Bax remained relatively constant. Although Bax was redistributed from the cytosol to the mitochondria, resulting in an increase in the mitochondrial level of Bax following NOC treatment, the subcellular localization of Bcl-2, Bim, Bak and apoptosis-inducing factor was confined to the mitochondrial fraction irrespective of NOC treatment. Experiments using selective caspase inhibitors showed that mitochondria-dependent activation of caspase-9 and -3 was crucial for NOC-induced apoptosis. NOC-induced phosphorylation of Bcl-2 and Bim, Δψm loss, and mitochondria-dependent apoptotic events were significantly suppressed by a Cdk1 inhibitor roscovitine, but not by the JNK inhibitor SP600125 or the p38 MAPK inhibitor SB203580. These results show that the prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim, which was mediated by Cdk1, could reduce the association of Bcl-2 with Bak or Bim to allow Bak activation and mitochondrial apoptotic events in Jurkat T cells exposed to NOC.

show abstract

Prometaphase arrest-dependent phosphorylation of Bcl-2 family proteins and activation of mitochondrial apoptotic pathway are associated with 17α-estradiol-induced apoptosis in human Jurkat T cells

Han

Jun

Kim

et al. 2013

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

View full text Add to dashboard Cite

In Jurkat T cell clone (JT/Neo), G2/M arrest, apoptotic sub-G1 peak, mitochondrial membrane potential (Δψm) loss, and TUNEL-positive DNA fragmentation were induced following exposure to 17α-estradiol (17α-E2), whereas none of these events (except for G2/M arrest) were induced in Jurkat cells overexpressing Bcl-2 (JT/Bcl-2). Under these conditions, phosphorylation at Thr161 and dephosphorylation at Tyr15 of Cdk1, upregulation of cyclin B1 level, histone H1 phosphorylation, Cdc25C phosphorylation at Thr-48, Bcl-2 phosphorylation at Thr-56 and Ser-70, Mcl-1 phosphorylation, and Bim phosphorylation were detected in the presence of Bcl-2 overexpression. However, the 17α-E2-induced upregulation of Bak levels, activation of Bak, activation of caspase-3, and PARP degradation were abrogated by Bcl-2 overexpression. In the presence of the G1/S blocking agent hydroxyurea, 17α-E2 failed to induce G2/M arrest and all apoptotic events including Cdk1 activation and phosphorylation of Bcl-2, Mcl-1 and Bim. The 17α-E2-induced phosphorylation of Bcl-2 family proteins and mitochondrial apoptotic events were suppressed by a Cdk1 inhibitor but not by aurora A and aurora B kinase inhibitors. Immunofluorescence microscopic analysis showed that an aberrant bipolar microtubule array, incomplete chromosome congression at the metaphase plate, and prometaphase arrest, which was reversible, were the underlying factors for 17α-E2-induced mitotic arrest. The in vitro microtubule polymerization assay showed that 17α-E2 could directly inhibit microtubule formation. These results show that the apoptogenic activity of 17α-E2 was due to the impaired mitotic spindle assembly causing prometaphase arrest and prolonged Cdk1 activation, the phosphorylation of Bcl-2, Mcl-1 and Bim, and the activation of Bak and mitochondria-dependent caspase cascade.

show abstract

Cyclin B1 interacts with the BH3-only protein Bim and mediates its phosphorylation by Cdk1 during mitosis

Cited by 24 publications

References 44 publications

BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

BimEL is phosphorylated at mitosis by Aurora A and targeted for degradation by βTrCP1

Prometaphase arrest-dependent phosphorylation of Bcl-2 and Bim reduces the association of Bcl-2 with Bak or Bim, provoking Bak activation and mitochondrial apoptosis in nocodazole-treated Jurkat T cells

Prometaphase arrest-dependent phosphorylation of Bcl-2 family proteins and activation of mitochondrial apoptotic pathway are associated with 17α-estradiol-induced apoptosis in human Jurkat T cells

Contact Info

Product

Resources

About