The microtubule-dependent motor centromere-associated protein E (CENP-E) is an integral component of kinetochore corona fibers that link centromeres to spindle microtubules.
Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Using immunoelectron microscopy, CENP-E is shown to be an integral component of the kinetochore corona fibers that tether centromeres to the spindle. Immediately upon nuclear envelope fragmentation, an associated plus end motor trafficks cytoplasmic CENP-E toward chromosomes along astral microtubules that enter the nuclear volume. Before or concurrently with initial lateral attachment of spindle microtubules, CENP-E targets to the outermost region of the developing kinetochores. After stable attachment, throughout chromosome congression, at metaphase, and throughout anaphase A, CENP-E is a constituent of the corona fibers, extending at least 50 nm away from the kinetochore outer plate and intertwining with spindle microtubules. In congressing chromosomes, CENP-E is preferentially associated with (or accessible at) the stretched, leading kinetochore known to provide the primary power for chromosome movement. Taken together, this evidence strongly supports a model in which CENP-E functions in congression to tether kinetochores to the disassembling microtubule plus ends.
Yao
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Laboratory of Cell Biology, Ludwig Institute for Cancer Research, School of Medicine, University of California, La Jolla, CA 92093-0660, USA.
Anderson
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Cleveland
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D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division; D002503:Centromere / Q000648:ultrastructure*; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis*; D002877:Chromosomes, Human / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000648:ultrastructure*; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000187:drug effects / Q000648:ultrastructure*; D008961:Models, Structural; D015739:Nocodazole / Q000494:pharmacology; D009685:Nuclear Envelope / Q000502:physiology / Q000648:ultrastructure; D008941:Spindle Apparatus / Q000648:ultrastructure
D002868:Chromosomal Proteins, Non-Histone; C068688:centromere protein E; D015739:Nocodazole