Limits...
Regulation of Sli15/INCENP, kinetochore, and Cdc14 phosphatase functions by the ribosome biogenesis protein Utp7.

Jwa M, Kim JH, Chan CS - J. Cell Biol. (2008)

Bottom Line: Before anaphase onset, it prevents the premature nucleolar release of Cdc14 and the premature concentration of Sli15 on the spindle.Furthermore, Utp7 can regulate the localization and phosphorylation status of Sli15 independent of its effect on Cdc14 function.Thus, Utp7 is a multifunctional protein that plays essential roles in the vital cellular processes of ribosome biogenesis, chromosome segregation, and cell cycle control.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cellular and Molecular Biology, The University of Texas, Austin, TX 78712, USA.

ABSTRACT
The Sli15-Ipl1-Bir1 chromosomal passenger complex is essential for proper kinetochore-microtubule attachment and spindle stability in the budding yeast Saccharomyces cerevisiae. During early anaphase, release of the Cdc14 protein phosphatase from the nucleolus leads to the dephosphorylation of Sli15 and redistribution of this complex from kinetochores to the spindle. We show here that the predominantly nucleolar ribosome biogenesis protein Utp7 is also present at kinetochores and is required for normal organization of kinetochore proteins and proper chromosome segregation. Utp7 associates with and regulates the localization of Sli15 and Cdc14. Before anaphase onset, it prevents the premature nucleolar release of Cdc14 and the premature concentration of Sli15 on the spindle. Furthermore, Utp7 can regulate the localization and phosphorylation status of Sli15 independent of its effect on Cdc14 function. Thus, Utp7 is a multifunctional protein that plays essential roles in the vital cellular processes of ribosome biogenesis, chromosome segregation, and cell cycle control.

Show MeSH
Sli15 and other kinetochore proteins mislocalize in utp7-26 cells. (A) Chromatin immunoprecipitation (ChIP) was performed with the antibodies shown, using extracts from wild-type, utp7-26, or sli15-3 cells that were incubated at 26°C and then shifted to 37°C for 3 h. PCR was performed as described in Fig. 1. (B) Immunoblotting of extracts from some of the cells used in A.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2542472&req=5

fig4: Sli15 and other kinetochore proteins mislocalize in utp7-26 cells. (A) Chromatin immunoprecipitation (ChIP) was performed with the antibodies shown, using extracts from wild-type, utp7-26, or sli15-3 cells that were incubated at 26°C and then shifted to 37°C for 3 h. PCR was performed as described in Fig. 1. (B) Immunoblotting of extracts from some of the cells used in A.

Mentions: We also checked by immunoprecipitation assays whether Utp7 might associate with Sli15, Ipl1, and Bir1. Our results showed that Utp7-HA could be coprecipitated with Sli15-Myc and Bir1-Myc but not with Ipl1-Myc (Fig. 1, B–D). Purification of GST-Utp7 also led to the copurification of Sli15 and a very small amount of Ipl1 (that could be detected only after long exposure; unpublished data). Because Sli15 exists in at least two complexes in yeast, one containing Bir1 and the other containing Bir1 and Ipl1 (Cheeseman et al., 2002; Sandall et al., 2006; Widlund et al., 2006), our results suggested that Utp7 may associate preferentially with the Sli15 complex that does not contain Ipl1. However, we cannot rule out the possibility that the failure to precipitate Utp7-HA with Ipl1-Myc may be caused by technical problems, such as masking of the Myc-epitope on Ipl1 in the presence of Utp7-HA. In spite of the association of Utp7 with Sli15 and Bir1, the centromere association of Utp7-HA is not affected in sli15-3 or ipl1-2 mutant cells (Fig. 1 A). Because the centromere association of Ipl1 and mutant Sli15 is abolished in sli15-3 cells (see Fig. 4 A; Emanuele et al., 2008), the kinetochore localization of Utp7 does not depend on the kinetochore localization of Sli15 or Ipl1.


Regulation of Sli15/INCENP, kinetochore, and Cdc14 phosphatase functions by the ribosome biogenesis protein Utp7.

Jwa M, Kim JH, Chan CS - J. Cell Biol. (2008)

Sli15 and other kinetochore proteins mislocalize in utp7-26 cells. (A) Chromatin immunoprecipitation (ChIP) was performed with the antibodies shown, using extracts from wild-type, utp7-26, or sli15-3 cells that were incubated at 26°C and then shifted to 37°C for 3 h. PCR was performed as described in Fig. 1. (B) Immunoblotting of extracts from some of the cells used in A.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2542472&req=5

fig4: Sli15 and other kinetochore proteins mislocalize in utp7-26 cells. (A) Chromatin immunoprecipitation (ChIP) was performed with the antibodies shown, using extracts from wild-type, utp7-26, or sli15-3 cells that were incubated at 26°C and then shifted to 37°C for 3 h. PCR was performed as described in Fig. 1. (B) Immunoblotting of extracts from some of the cells used in A.
Mentions: We also checked by immunoprecipitation assays whether Utp7 might associate with Sli15, Ipl1, and Bir1. Our results showed that Utp7-HA could be coprecipitated with Sli15-Myc and Bir1-Myc but not with Ipl1-Myc (Fig. 1, B–D). Purification of GST-Utp7 also led to the copurification of Sli15 and a very small amount of Ipl1 (that could be detected only after long exposure; unpublished data). Because Sli15 exists in at least two complexes in yeast, one containing Bir1 and the other containing Bir1 and Ipl1 (Cheeseman et al., 2002; Sandall et al., 2006; Widlund et al., 2006), our results suggested that Utp7 may associate preferentially with the Sli15 complex that does not contain Ipl1. However, we cannot rule out the possibility that the failure to precipitate Utp7-HA with Ipl1-Myc may be caused by technical problems, such as masking of the Myc-epitope on Ipl1 in the presence of Utp7-HA. In spite of the association of Utp7 with Sli15 and Bir1, the centromere association of Utp7-HA is not affected in sli15-3 or ipl1-2 mutant cells (Fig. 1 A). Because the centromere association of Ipl1 and mutant Sli15 is abolished in sli15-3 cells (see Fig. 4 A; Emanuele et al., 2008), the kinetochore localization of Utp7 does not depend on the kinetochore localization of Sli15 or Ipl1.

Bottom Line: Before anaphase onset, it prevents the premature nucleolar release of Cdc14 and the premature concentration of Sli15 on the spindle.Furthermore, Utp7 can regulate the localization and phosphorylation status of Sli15 independent of its effect on Cdc14 function.Thus, Utp7 is a multifunctional protein that plays essential roles in the vital cellular processes of ribosome biogenesis, chromosome segregation, and cell cycle control.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cellular and Molecular Biology, The University of Texas, Austin, TX 78712, USA.

ABSTRACT
The Sli15-Ipl1-Bir1 chromosomal passenger complex is essential for proper kinetochore-microtubule attachment and spindle stability in the budding yeast Saccharomyces cerevisiae. During early anaphase, release of the Cdc14 protein phosphatase from the nucleolus leads to the dephosphorylation of Sli15 and redistribution of this complex from kinetochores to the spindle. We show here that the predominantly nucleolar ribosome biogenesis protein Utp7 is also present at kinetochores and is required for normal organization of kinetochore proteins and proper chromosome segregation. Utp7 associates with and regulates the localization of Sli15 and Cdc14. Before anaphase onset, it prevents the premature nucleolar release of Cdc14 and the premature concentration of Sli15 on the spindle. Furthermore, Utp7 can regulate the localization and phosphorylation status of Sli15 independent of its effect on Cdc14 function. Thus, Utp7 is a multifunctional protein that plays essential roles in the vital cellular processes of ribosome biogenesis, chromosome segregation, and cell cycle control.

Show MeSH