4aj5
From Proteopedia
Crystal structure of the Ska core complex
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 PubMedThe 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
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