Limits...
Tension sensing by Aurora B kinase is independent of survivin-based centromere localization.

Campbell CS, Desai A - Nature (2013)

Bottom Line: Unlike wild-type Sli15, truncated Sli15 localizes to pre-anaphase spindle microtubules.Premature targeting of full-length Sli15 to microtubules by preventing Cdk1 (also known as Cdc28) phosphorylation also suppresses the inviability of Bir1 deletion.These results suggest that activation of Aurora B kinase by clustering either on chromatin or on microtubules is sufficient for chromosome biorientation.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA.

ABSTRACT
Accurate segregation of the replicated genome requires chromosome biorientation on the spindle. Biorientation is ensured by Aurora B kinase (Ipl1), a member of the four-subunit chromosomal passenger complex (CPC). Localization of the CPC to the inner centromere is central to the current model for how tension ensures chromosome biorientation: kinetochore-spindle attachments that are not under tension remain close to the inner centromere and are destabilized by Aurora B phosphorylation, whereas kinetochores under tension are pulled away from the influence of Aurora B, stabilizing their microtubule attachments. Here we show that an engineered truncation of the Sli15 (known as INCENP in humans) subunit of budding yeast CPC that eliminates association with the inner centromere nevertheless supports proper chromosome segregation during both mitosis and meiosis. Truncated Sli15 suppresses the deletion phenotypes of the inner-centromere-targeting proteins survivin (Bir1), borealin (Nbl1), Bub1 and Sgo1 (ref. 6). Unlike wild-type Sli15, truncated Sli15 localizes to pre-anaphase spindle microtubules. Premature targeting of full-length Sli15 to microtubules by preventing Cdk1 (also known as Cdc28) phosphorylation also suppresses the inviability of Bir1 deletion. These results suggest that activation of Aurora B kinase by clustering either on chromatin or on microtubules is sufficient for chromosome biorientation.

Show MeSH

Related in: MedlinePlus

Deletion of the Sli15 N-terminus prevents association with Bir1 but does not affect cell viability or growth(a) Schematic of the CPC in budding yeast. Sli15=INCENP; Bir1=Survivin; Nbl1=Borealin/Dasra and Ipl1=Aurora B kinase.(b) Phenotype of bir1Δ. Tetrad dissections from a bir1Δ heterozygote—the 4 spores from individual tetrads are arrayed in columns. Rare survivors (referred to as bir1Δ*) are observed after extended growth (right panel).(c) Phenotype of Sli15 truncations. Tetrad dissections from a sli15ΔNT heterozygote are shown on the right.(d) Co-immunoprecipitation analysis of full length (FL) Sli15 or Sli15ΔNT and Bir1. 9Myc and 6HA tags were inserted at endogenous loci to generate functional C-terminally tagged proteins. Bir1 coimmunoprecipitates with FL Sli15 but not with Sli15ΔNT.(e) Localization of Sli15-Venus and Sli15ΔN-Venus to the anaphase spindle. Scale bar is 5 μm.(f) Localization of CPC components during anaphase in cells with either wildtype Sli15 or Sli15ΔNT. Scale bar is 5 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3644022&req=5

Figure 1: Deletion of the Sli15 N-terminus prevents association with Bir1 but does not affect cell viability or growth(a) Schematic of the CPC in budding yeast. Sli15=INCENP; Bir1=Survivin; Nbl1=Borealin/Dasra and Ipl1=Aurora B kinase.(b) Phenotype of bir1Δ. Tetrad dissections from a bir1Δ heterozygote—the 4 spores from individual tetrads are arrayed in columns. Rare survivors (referred to as bir1Δ*) are observed after extended growth (right panel).(c) Phenotype of Sli15 truncations. Tetrad dissections from a sli15ΔNT heterozygote are shown on the right.(d) Co-immunoprecipitation analysis of full length (FL) Sli15 or Sli15ΔNT and Bir1. 9Myc and 6HA tags were inserted at endogenous loci to generate functional C-terminally tagged proteins. Bir1 coimmunoprecipitates with FL Sli15 but not with Sli15ΔNT.(e) Localization of Sli15-Venus and Sli15ΔN-Venus to the anaphase spindle. Scale bar is 5 μm.(f) Localization of CPC components during anaphase in cells with either wildtype Sli15 or Sli15ΔNT. Scale bar is 5 μm.

Mentions: All known mechanisms targeting the CPC to centromeric chromatin, in budding yeast and elsewhere, rely on the Survivin/Bir1 subunit. Budding yeast CPC (Fig. 1a) is targeted by two Bir1-dependent mechanisms: interaction of Bir1 with Sgo1, which recognizes histone H2a phosphorylated by the kinetochore-localized kinase Bub16, and direct binding of Bir1 to the Ndc10 subunit of the centromeric DNA-binding complex CBF37,8. In other species, Survivin binding to histone H3 phosphorylated on threonine 3 by Haspin kinase is also implicated in CPC centromere targeting9–11; however, deletion of the two haspin-like genes (Alk1 and Alk2) does not lead to a growth phenotype (see below) suggesting that this mechanism may not operate in budding yeast.


Tension sensing by Aurora B kinase is independent of survivin-based centromere localization.

Campbell CS, Desai A - Nature (2013)

Deletion of the Sli15 N-terminus prevents association with Bir1 but does not affect cell viability or growth(a) Schematic of the CPC in budding yeast. Sli15=INCENP; Bir1=Survivin; Nbl1=Borealin/Dasra and Ipl1=Aurora B kinase.(b) Phenotype of bir1Δ. Tetrad dissections from a bir1Δ heterozygote—the 4 spores from individual tetrads are arrayed in columns. Rare survivors (referred to as bir1Δ*) are observed after extended growth (right panel).(c) Phenotype of Sli15 truncations. Tetrad dissections from a sli15ΔNT heterozygote are shown on the right.(d) Co-immunoprecipitation analysis of full length (FL) Sli15 or Sli15ΔNT and Bir1. 9Myc and 6HA tags were inserted at endogenous loci to generate functional C-terminally tagged proteins. Bir1 coimmunoprecipitates with FL Sli15 but not with Sli15ΔNT.(e) Localization of Sli15-Venus and Sli15ΔN-Venus to the anaphase spindle. Scale bar is 5 μm.(f) Localization of CPC components during anaphase in cells with either wildtype Sli15 or Sli15ΔNT. Scale bar is 5 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3644022&req=5

Figure 1: Deletion of the Sli15 N-terminus prevents association with Bir1 but does not affect cell viability or growth(a) Schematic of the CPC in budding yeast. Sli15=INCENP; Bir1=Survivin; Nbl1=Borealin/Dasra and Ipl1=Aurora B kinase.(b) Phenotype of bir1Δ. Tetrad dissections from a bir1Δ heterozygote—the 4 spores from individual tetrads are arrayed in columns. Rare survivors (referred to as bir1Δ*) are observed after extended growth (right panel).(c) Phenotype of Sli15 truncations. Tetrad dissections from a sli15ΔNT heterozygote are shown on the right.(d) Co-immunoprecipitation analysis of full length (FL) Sli15 or Sli15ΔNT and Bir1. 9Myc and 6HA tags were inserted at endogenous loci to generate functional C-terminally tagged proteins. Bir1 coimmunoprecipitates with FL Sli15 but not with Sli15ΔNT.(e) Localization of Sli15-Venus and Sli15ΔN-Venus to the anaphase spindle. Scale bar is 5 μm.(f) Localization of CPC components during anaphase in cells with either wildtype Sli15 or Sli15ΔNT. Scale bar is 5 μm.
Mentions: All known mechanisms targeting the CPC to centromeric chromatin, in budding yeast and elsewhere, rely on the Survivin/Bir1 subunit. Budding yeast CPC (Fig. 1a) is targeted by two Bir1-dependent mechanisms: interaction of Bir1 with Sgo1, which recognizes histone H2a phosphorylated by the kinetochore-localized kinase Bub16, and direct binding of Bir1 to the Ndc10 subunit of the centromeric DNA-binding complex CBF37,8. In other species, Survivin binding to histone H3 phosphorylated on threonine 3 by Haspin kinase is also implicated in CPC centromere targeting9–11; however, deletion of the two haspin-like genes (Alk1 and Alk2) does not lead to a growth phenotype (see below) suggesting that this mechanism may not operate in budding yeast.

Bottom Line: Unlike wild-type Sli15, truncated Sli15 localizes to pre-anaphase spindle microtubules.Premature targeting of full-length Sli15 to microtubules by preventing Cdk1 (also known as Cdc28) phosphorylation also suppresses the inviability of Bir1 deletion.These results suggest that activation of Aurora B kinase by clustering either on chromatin or on microtubules is sufficient for chromosome biorientation.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92037, USA.

ABSTRACT
Accurate segregation of the replicated genome requires chromosome biorientation on the spindle. Biorientation is ensured by Aurora B kinase (Ipl1), a member of the four-subunit chromosomal passenger complex (CPC). Localization of the CPC to the inner centromere is central to the current model for how tension ensures chromosome biorientation: kinetochore-spindle attachments that are not under tension remain close to the inner centromere and are destabilized by Aurora B phosphorylation, whereas kinetochores under tension are pulled away from the influence of Aurora B, stabilizing their microtubule attachments. Here we show that an engineered truncation of the Sli15 (known as INCENP in humans) subunit of budding yeast CPC that eliminates association with the inner centromere nevertheless supports proper chromosome segregation during both mitosis and meiosis. Truncated Sli15 suppresses the deletion phenotypes of the inner-centromere-targeting proteins survivin (Bir1), borealin (Nbl1), Bub1 and Sgo1 (ref. 6). Unlike wild-type Sli15, truncated Sli15 localizes to pre-anaphase spindle microtubules. Premature targeting of full-length Sli15 to microtubules by preventing Cdk1 (also known as Cdc28) phosphorylation also suppresses the inviability of Bir1 deletion. These results suggest that activation of Aurora B kinase by clustering either on chromatin or on microtubules is sufficient for chromosome biorientation.

Show MeSH
Related in: MedlinePlus