Kinetochore-dependent microtubule rescue ensures their efficient and sustained interactions in early mitosis.
Bottom Line: Meanwhile, microtubule rescue distal to the kinetochore is also promoted by Stu2, which is transported by a kinesin-8 motor Kip3 along the microtubule from the kinetochore.Microtubule extension following rescue facilitates interaction with other widely scattered kinetochores, diminishing long delays in collecting the complete set of kinetochores by microtubules.Thus, kinetochore-dependent microtubule rescue ensures efficient and sustained kinetochore-microtubule interactions in early mitosis.
Affiliation: Wellcome Trust Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.Show MeSH
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Mentions: Establishment of end-on attachment (which is verified by subsequent end-on pulling) is probably crucial for subsequent sister KT biorientation (Maure et al., 2011; Tanaka, 2010). However, if end-on attachment is the essential next step for KT-MT interaction, what are the benefits of KT-dependent MT rescue, which extends the duration of lateral attachment and seems to delay establishment of end-on attachment? A clue to this question was obtained regarding MT rescue at the KT, when we recently studied mutants of the Ndc80 loop region (Maure et al., 2011), a distinct motif looping out from the coiled-coil shaft of the Ndc80 complex (see Figure 2Bi). These mutants were defective in forming end-on attachment; indeed, when the MT plus end caught up with a laterally associated KT, end-on attachment was rarely established. Given this, we expected that KTs would detach from MT ends in these mutants. However, this was rare, and instead MT rescue at the KT happened in most cases (Maure et al., 2011). This raised the possibility that MT rescue at a KT may happen, following failure to achieve end-on attachment.
Affiliation: Wellcome Trust Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.