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CSC-1: a subunit of the Aurora B kinase complex that binds to the survivin-like protein BIR-1 and the incenp-like protein ICP-1.

Romano A, Guse A, Krascenicova I, Schnabel H, Schnabel R, Glotzer M - J. Cell Biol. (2003)

Bottom Line: CSC-1 associates with ICP-1, BIR-1, and AIR-2 in vivo.ICP-1 dramatically stimulates AIR-2 kinase activity.This activity is not stimulated by CSC-1/BIR-1, suggesting that these two subunits function as targeting subunits for AIR-2 kinase.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Molecular Pathology, Dr. Bohrgasse 7, Vienna A-1030, Austria.

ABSTRACT
The Aurora B kinase complex is a critical regulator of chromosome segregation and cytokinesis. In Caenorhabditis elegans, AIR-2 (Aurora B) function requires ICP-1 (Incenp) and BIR-1 (Survivin). In various systems, Aurora B binds to orthologues of these proteins. Through genetic analysis, we have identified a new subunit of the Aurora B kinase complex, CSC-1. C. elegans embryos depleted of CSC-1, AIR-2, ICP-1, or BIR-1 have identical phenotypes. CSC-1, BIR-1, and ICP-1 are interdependent for their localization, and all are required for AIR-2 localization. In vitro, CSC-1 binds directly to BIR-1. The CSC-1/BIR-1 complex, but not the individual subunits, associates with ICP-1. CSC-1 associates with ICP-1, BIR-1, and AIR-2 in vivo. ICP-1 dramatically stimulates AIR-2 kinase activity. This activity is not stimulated by CSC-1/BIR-1, suggesting that these two subunits function as targeting subunits for AIR-2 kinase.

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CSC-1 localizes in a similar manner as ABI complex members. CSC-1 localization in wild-type embryos was analyzed by immunofluorescence. Staining is observed in the central region of meiotic bivalents during diakinesis (A) and in prometaphase (B) of meiosis I. At anaphase I, CSC-1 localizes to the central region of the meiotic spindle (C). During mitotic metaphase, CSC-1 localizes to the chromosomes (D), and in anaphase, it localizes to the central spindle (E). The CSC-1 signal on the central spindle is wider than that of the centralspindlin component ZEN-4 (F). The above-mentioned staining patterns are absent in csc-1(RNAi) embryos (G); anti-tubulin staining demonstrates antibody accessibility (H).
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fig2: CSC-1 localizes in a similar manner as ABI complex members. CSC-1 localization in wild-type embryos was analyzed by immunofluorescence. Staining is observed in the central region of meiotic bivalents during diakinesis (A) and in prometaphase (B) of meiosis I. At anaphase I, CSC-1 localizes to the central region of the meiotic spindle (C). During mitotic metaphase, CSC-1 localizes to the chromosomes (D), and in anaphase, it localizes to the central spindle (E). The CSC-1 signal on the central spindle is wider than that of the centralspindlin component ZEN-4 (F). The above-mentioned staining patterns are absent in csc-1(RNAi) embryos (G); anti-tubulin staining demonstrates antibody accessibility (H).

Mentions: To examine whether CSC-1 shows the same subcellular location as other ABI complex members, a peptide-specific antibody was prepared and used to detect CSC-1 in wild-type embryos. In oocytes, during meiosis I, CSC-1 localizes to a discrete region of meiotic bivalents (Fig. 2, A and B) . During anaphase of meiosis I, CSC-1 localizes to the midzone of the meiotic spindle (Fig. 2 C). In mitosis, CSC-1 localizes to chromosomes during metaphase (Fig. 2 D) and to the spindle midzone during anaphase (Fig. 2 E) and telophase. The localization of CSC-1 on the central spindle is significantly broader than the localization of ZEN-4, the kinesin-like protein that is part of the centralspindlin complex (Fig. 2 F). The reactivity of anti–CSC-1 antibodies on chromatin (Fig. 2 G) and the central spindle is abolished in csc-1(RNAi) embryos. All features of the localization of CSC-1 are similar to those described for other members of the ABI complex (Schumacher et al., 1998; Severson et al., 2000; Oegema et al., 2001; Kaitna et al., 2002; Rogers et al., 2002).


CSC-1: a subunit of the Aurora B kinase complex that binds to the survivin-like protein BIR-1 and the incenp-like protein ICP-1.

Romano A, Guse A, Krascenicova I, Schnabel H, Schnabel R, Glotzer M - J. Cell Biol. (2003)

CSC-1 localizes in a similar manner as ABI complex members. CSC-1 localization in wild-type embryos was analyzed by immunofluorescence. Staining is observed in the central region of meiotic bivalents during diakinesis (A) and in prometaphase (B) of meiosis I. At anaphase I, CSC-1 localizes to the central region of the meiotic spindle (C). During mitotic metaphase, CSC-1 localizes to the chromosomes (D), and in anaphase, it localizes to the central spindle (E). The CSC-1 signal on the central spindle is wider than that of the centralspindlin component ZEN-4 (F). The above-mentioned staining patterns are absent in csc-1(RNAi) embryos (G); anti-tubulin staining demonstrates antibody accessibility (H).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2172917&req=5

fig2: CSC-1 localizes in a similar manner as ABI complex members. CSC-1 localization in wild-type embryos was analyzed by immunofluorescence. Staining is observed in the central region of meiotic bivalents during diakinesis (A) and in prometaphase (B) of meiosis I. At anaphase I, CSC-1 localizes to the central region of the meiotic spindle (C). During mitotic metaphase, CSC-1 localizes to the chromosomes (D), and in anaphase, it localizes to the central spindle (E). The CSC-1 signal on the central spindle is wider than that of the centralspindlin component ZEN-4 (F). The above-mentioned staining patterns are absent in csc-1(RNAi) embryos (G); anti-tubulin staining demonstrates antibody accessibility (H).
Mentions: To examine whether CSC-1 shows the same subcellular location as other ABI complex members, a peptide-specific antibody was prepared and used to detect CSC-1 in wild-type embryos. In oocytes, during meiosis I, CSC-1 localizes to a discrete region of meiotic bivalents (Fig. 2, A and B) . During anaphase of meiosis I, CSC-1 localizes to the midzone of the meiotic spindle (Fig. 2 C). In mitosis, CSC-1 localizes to chromosomes during metaphase (Fig. 2 D) and to the spindle midzone during anaphase (Fig. 2 E) and telophase. The localization of CSC-1 on the central spindle is significantly broader than the localization of ZEN-4, the kinesin-like protein that is part of the centralspindlin complex (Fig. 2 F). The reactivity of anti–CSC-1 antibodies on chromatin (Fig. 2 G) and the central spindle is abolished in csc-1(RNAi) embryos. All features of the localization of CSC-1 are similar to those described for other members of the ABI complex (Schumacher et al., 1998; Severson et al., 2000; Oegema et al., 2001; Kaitna et al., 2002; Rogers et al., 2002).

Bottom Line: CSC-1 associates with ICP-1, BIR-1, and AIR-2 in vivo.ICP-1 dramatically stimulates AIR-2 kinase activity.This activity is not stimulated by CSC-1/BIR-1, suggesting that these two subunits function as targeting subunits for AIR-2 kinase.

View Article: PubMed Central - PubMed

Affiliation: Research Institute of Molecular Pathology, Dr. Bohrgasse 7, Vienna A-1030, Austria.

ABSTRACT
The Aurora B kinase complex is a critical regulator of chromosome segregation and cytokinesis. In Caenorhabditis elegans, AIR-2 (Aurora B) function requires ICP-1 (Incenp) and BIR-1 (Survivin). In various systems, Aurora B binds to orthologues of these proteins. Through genetic analysis, we have identified a new subunit of the Aurora B kinase complex, CSC-1. C. elegans embryos depleted of CSC-1, AIR-2, ICP-1, or BIR-1 have identical phenotypes. CSC-1, BIR-1, and ICP-1 are interdependent for their localization, and all are required for AIR-2 localization. In vitro, CSC-1 binds directly to BIR-1. The CSC-1/BIR-1 complex, but not the individual subunits, associates with ICP-1. CSC-1 associates with ICP-1, BIR-1, and AIR-2 in vivo. ICP-1 dramatically stimulates AIR-2 kinase activity. This activity is not stimulated by CSC-1/BIR-1, suggesting that these two subunits function as targeting subunits for AIR-2 kinase.

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