| Structural highlights
Function
[SKA3_HUMAN] Component of the SKA1 complex, a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. The SKA1 complex is a direct component of the kinetochore-microtubule interface and directly associates with microtubules as oligomeric assemblies. The complex facilitates the processive movement of microspheres along a microtubule in a depolymerization-coupled manner. In the complex, it mediates the microtubule-stimulated oligomerization.[1] [2] [SKA2_HUMAN] Component of the SKA1 complex, a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. Required for timely anaphase onset during mitosis, when chromosomes undergo bipolar attachment on spindle microtubules leading to silencing of the spindle checkpoint. The SKA1 complex is a direct component of the kinetochore-microtubule interface and directly associates with microtubules as oligomeric assemblies. The complex facilitates the processive movement of microspheres along a microtubule in a depolymerization-coupled manner. In the complex, it is required for SKA1 localization.[3] [4] [SKA1_HUMAN] Component of the SKA1 complex, a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. Required for timely anaphase onset during mitosis, when chromosomes undergo bipolar attachment on spindle microtubules leading to silencing of the spindle checkpoint. The SKA1 complex is a direct component of the kinetochore-microtubule interface and directly associates with microtubules as oligomeric assemblies. The complex facilitates the processive movement of microspheres along a microtubule in a depolymerization-coupled manner. In the complex, it mediates the interaction with microtubules.[5] [6]
Publication Abstract from PubMed
The Ska complex is an essential mitotic component required for accurate cell division in human cells. It is composed of three subunits that function together to establish stable kinetochore-microtubule interactions in concert with the Ndc80 network. We show that the structure of the Ska core complex is a W-shaped dimer of coiled coils, formed by intertwined interactions between Ska1, Ska2, and Ska3. The C-terminal domains of Ska1 and Ska3 protrude at each end of the homodimer, bind microtubules in vitro when connected to the central core, and are essential in vivo. Mutations disrupting the central coiled coil or the dimerization interface result in chromosome congression failure followed by cell death. The Ska complex is thus endowed with bipartite and cooperative tubulin-binding properties at the ends of a 350 A-long molecule. We discuss how this symmetric architecture might complement and stabilize the Ndc80-microtubule attachments with analogies to the yeast Dam1/DASH complex.
Structural and functional organization of the ska complex, a key component of the kinetochore-microtubule interface.,Jeyaprakash AA, Santamaria A, Jayachandran U, Chan YW, Benda C, Nigg EA, Conti E Mol Cell. 2012 May 11;46(3):274-86. Epub 2012 Apr 5. PMID:22483620[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Welburn JP, Grishchuk EL, Backer CB, Wilson-Kubalek EM, Yates JR 3rd, Cheeseman IM. The human kinetochore Ska1 complex facilitates microtubule depolymerization-coupled motility. Dev Cell. 2009 Mar;16(3):374-85. PMID:19289083 doi:http://dx.doi.org/S1534-5807(09)00039-2
- ↑ Gaitanos TN, Santamaria A, Jeyaprakash AA, Wang B, Conti E, Nigg EA. Stable kinetochore-microtubule interactions depend on the Ska complex and its new component Ska3/C13Orf3. EMBO J. 2009 May 20;28(10):1442-52. doi: 10.1038/emboj.2009.96. Epub 2009 Apr 9. PMID:19360002 doi:http://dx.doi.org/10.1038/emboj.2009.96
- ↑ Hanisch A, Sillje HH, Nigg EA. Timely anaphase onset requires a novel spindle and kinetochore complex comprising Ska1 and Ska2. EMBO J. 2006 Nov 29;25(23):5504-15. Epub 2006 Nov 9. PMID:17093495 doi:http://dx.doi.org/10.1038/sj.emboj.7601426
- ↑ Welburn JP, Grishchuk EL, Backer CB, Wilson-Kubalek EM, Yates JR 3rd, Cheeseman IM. The human kinetochore Ska1 complex facilitates microtubule depolymerization-coupled motility. Dev Cell. 2009 Mar;16(3):374-85. PMID:19289083 doi:http://dx.doi.org/S1534-5807(09)00039-2
- ↑ Hanisch A, Sillje HH, Nigg EA. Timely anaphase onset requires a novel spindle and kinetochore complex comprising Ska1 and Ska2. EMBO J. 2006 Nov 29;25(23):5504-15. Epub 2006 Nov 9. PMID:17093495 doi:http://dx.doi.org/10.1038/sj.emboj.7601426
- ↑ Welburn JP, Grishchuk EL, Backer CB, Wilson-Kubalek EM, Yates JR 3rd, Cheeseman IM. The human kinetochore Ska1 complex facilitates microtubule depolymerization-coupled motility. Dev Cell. 2009 Mar;16(3):374-85. PMID:19289083 doi:http://dx.doi.org/S1534-5807(09)00039-2
- ↑ Jeyaprakash AA, Santamaria A, Jayachandran U, Chan YW, Benda C, Nigg EA, Conti E. Structural and functional organization of the ska complex, a key component of the kinetochore-microtubule interface. Mol Cell. 2012 May 11;46(3):274-86. Epub 2012 Apr 5. PMID:22483620 doi:10.1016/j.molcel.2012.03.005
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