Role of Hcn1 and Its Phosphorylation in Fission Yeast Anaphase-promoting Complex/Cyclosome Function

Yoon, Hyun-Joo; Feoktistova, Anna; Chen, Jun‐Song; Jennings, Jennifer L.; Link, Andrew J.; Gould, Kathleen L.

doi:10.1074/jbc.m603867200

Cited by 19 publications

(21 citation statements)

References 61 publications

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“…First, Atf1 displays genetic interactions with Apc5. Second, Apc4 works together or in close relationship with Apc5 to control APC/C activity, in agreement with previous reports (6,10,32). Indeed, we also observed that overexpression of apc5 ϩ rescued the apc4/cut20-100 ts mutant strain.…”

Section: Overexpression Of Atf1supporting

confidence: 81%

The Transcription Factor Atf1 Binds and Activates the APC/C Ubiquitin Ligase in Fission Yeast

Ors

Grimaldi

Kimata

et al. 2009

Journal of Biological Chemistry

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Fission yeast Atf1 is a member of the ATF/CREB basic leucine zipper (bZIP) family of transcription factors with strong homology to mammalian ATF2. Atf1 regulates transcription in response to stress stimuli and also plays a role in controlling heterochromatin formation and recombination. However, its DNA binding independent role is poorly studied. Here, we report that Atf1 has a distinct role in regulating the anaphasepromoting complex/cyclosome (APC/C) ubiquitin ligase. We have identified atf1؉ as a dose-dependent suppressor of apc5-1, a mutation causing mitotic arrest. Remarkably, the suppression is not dependent upon the bZIP domain and is therefore independent of the ability of Atf1 to bind DNA. Interestingly, Atf1 physically binds the APC/C in vivo. Furthermore, we show that addition of purified Atf1 proteins into a cell-free system stimulates ubiquitylation of cyclin B and securin by the APC/C. These results reveal a novel role for Atf1 in cell cycle control through protein-protein interaction.Ubiquitylation is a post-translational modification that occurs through the action of an enzymatic cascade consisting of three enzymes E1, E2, and E3, and typically controls the proteolysis, localization, or activity of a protein (1). It is a tightly regulated, highly specific and temporally controlled process, and thus plays an important role in many processes such as the cell cycle, signal transduction, transcription, DNA repair, development, and regulation of the immune response.The anaphase-promoting complex/cyclosome (APC/C) 2 is a large (1.5 MDa) multisubunit E3 ubiquitin ligase, which has essential functions in key events during the cell cycle, such as chromosome segregation and mitotic exit by degrading securin/Cut2/Pds1 and cyclin B/Cdc13/Clb2, respectively (2-4). The APC/C belongs to the RING finger family of E3 ubiquitin ligases, which include Ubr1, c-Cbl, and Skp1-Cullin 1-F-box (SCF) complex (5), but unlike other members of this family, it is exceptionally large and complex, consisting of at least 11 conserved subunits. The APC/C appears to consist of two separable subcomplexes which associate independently with the scaffold subunit, Apc1/Cut4 (6). The first subcomplex includes a RING finger subunit Apc11 and a cullin domain subunit Apc2. This subcomplex is capable of ubiquitylating proteins to some extent, but lacks substrate specificity (7-9). The specificity seems to rely on the second subcomplex, consisting of three subunits Apc3/Nuc2/Cdc27, Apc6/Cut9/Cdc16, and Apc8/Cut23/Cdc23, which contain a tetratricopeptide repeat (TPR) domain. A member of the Fizzy family of APC/C activators, Cdh1, has been shown to bind Apc3/Cdc27 via its C-terminal IR motifs and recruit a substrate to the APC/C (10 -12). However, the exact roles of the remaining subunits and other TPR subunits, such as Apc5 and Apc7, are unknown.The activity of the APC/C is regulated in part by the association of the Fizzy family of WD40-containing activator proteins (2-4). There are two major activators during the cell cycle, Fizzy/Slp1/Cdc2...

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Section: Overexpression Of Atf1supporting

confidence: 81%

The Transcription Factor Atf1 Binds and Activates the APC/C Ubiquitin Ligase in Fission Yeast

Ors

Grimaldi

Kimata

et al. 2009

Journal of Biological Chemistry

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“…Deletion of APC13 in yeast prevents stable association of APC3/Cdc27 and APC6/Cdc16 with the APC/C holocomplex (Schwickart et al, 2004). Furthermore, deletion of Hcn1/Cdc26 in fission yeast causes disassembly of the APC/C into at least two subcomplexes, one containing the platform (APC1, 2, 4, 5 and 11) and one containing the other components (Yoon et al, 2006). The only report of a direct interactor of APC16 is the RING finger domain of Rb binding protein 6 (Chibi et al, 2008), suggesting APC16 may possibly interact with the APC11 RING finger.…”

Section: Apc16 Is Not Required For Structural Integrity Of the Apc/c mentioning

confidence: 99%

APC16 is a conserved subunit of the anaphase-promoting complex/cyclosome

Kops

Voet

Manak

et al. 2010

Journal of Cell Science

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SummaryError-free chromosome segregation depends on timely activation of the multi-subunit E3 ubiquitin ligase APC/C. Activation of the APC/C initiates chromosome segregation and mitotic exit by targeting critical cell-cycle regulators for destruction. The APC/C is the principle target of the mitotic checkpoint, which prevents segregation while chromosomes are unattached to spindle microtubules. We now report the identification and characterization of APC16, a conserved subunit of the APC/C. APC16 was found in association with tandem-affinity-purified mitotic checkpoint complex protein complexes. APC16 is a bona fide subunit of human APC/C: it is present in APC/C complexes throughout the cell cycle, the phenotype of APC16-depleted cells copies depletion of other APC/C subunits, and APC16 is important for APC/C activity towards mitotic substrates. APC16 sequence homologues can be identified in metazoans, but not fungi, by four conserved primary sequence stretches. We provide evidence that the C. elegans gene K10D2.4 and the D. rerio gene zgc:110659 are functional equivalents of human APC16. Our findings show that APC/C is composed of previously undescribed subunits, and raise the question of why metazoan APC/C is molecularly different from unicellular APC/C.

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“…1B and C ). In fission yeast, Cdc26 (Hcn1) is phosphorylated at Ser48 in the mid-region of the protein, which corresponds to the consensus Cdk1 phosphorylation site [33]. However, a previous study showed that substitution of Ser48 with Asp had no effect on APC/C function; hence, the functional role of phosphorylation of this residue is somewhat uncertain.…”

Section: Discussionmentioning

confidence: 99%

“…However, a previous study showed that substitution of Ser48 with Asp had no effect on APC/C function; hence, the functional role of phosphorylation of this residue is somewhat uncertain. [33] Human CDC26 contains nine candidate Ser/Thr phosphorylation sites ( Fig. 1B ); however, only the T7 residue is conserved among vertebrates ( Fig.…”

Section: Discussionmentioning

confidence: 99%

LATS1 and LATS2 Phosphorylate CDC26 to Modulate Assembly of the Tetratricopeptide Repeat Subcomplex of APC/C

et al. 2015

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In budding yeast, the Mitotic Exit Network (MEN) regulates anaphase promoting complex/cyclosome (APC/C) via the Dbf2-Cdc14 signaling cascade. Dbf2 kinase phosphorylates and activates Cdc14 phosphatase, which removes the inhibitory phosphorylation of the APC/C cofactor Cdh1. Although each component of the MEN was highly conserved during evolution, there is presently no evidence supporting direct phosphorylation of CDC14 by large tumor suppressor kinase 1 (LATS1), the human counterpart of Dbf2; hence, it is unclear how LATS1 regulates APC/C. Here, we demonstrate that LATS1 phosphorylates the Thr7 (T7) residue of the APC/C component CDC26 directly. Nocodazole-induced phosphorylation of T7 was reduced by knockdown of LATS1 and LATS2 in HeLa cells, indicating that both of these kinases contribute to the phosphorylation of CDC26 in vivo. The T7 residue of CDC26 is critical for its interaction with APC6, a tetratricopeptide repeat-containing subunit of APC/C, and mutation of this residue to Asp (T7D) reduced the interaction of CDC26 with APC6. Replacement of endogenous CDC26 in HeLa cells with exogenous phosphor-mimic T7D-mutated CDC26 increased the elution size of APC/C subunits in a gel filtration assay, implying a change in the APC/C assembly upon phosphorylation of CDC26. Furthermore, T7D-mutated CDC26 promoted the ubiquitination of polo-like kinase 1, a well-known substrate of APC/C. Overall, these results suggest that LATS1/2 are novel kinases involved in APC/C phosphorylation and indicate a direct regulatory link between LATS1/2 and APC/C.

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Role of Hcn1 and Its Phosphorylation in Fission Yeast Anaphase-promoting Complex/Cyclosome Function

Cited by 19 publications

References 61 publications

The Transcription Factor Atf1 Binds and Activates the APC/C Ubiquitin Ligase in Fission Yeast

The Transcription Factor Atf1 Binds and Activates the APC/C Ubiquitin Ligase in Fission Yeast

APC16 is a conserved subunit of the anaphase-promoting complex/cyclosome

LATS1 and LATS2 Phosphorylate CDC26 to Modulate Assembly of the Tetratricopeptide Repeat Subcomplex of APC/C

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