EB1 Targets to Kinetochores with Attached, Polymerizing Microtubules
AUTOR(ES)
Tirnauer, Jennifer S.
FONTE
The American Society for Cell Biology
RESUMO
Microtubule polymerization dynamics at kinetochores is coupled to chromosome movements, but its regulation there is poorly understood. The plus end tracking protein EB1 is required both for regulating microtubule dynamics and for maintaining a euploid genome. To address the role of EB1 in aneuploidy, we visualized its targeting in mitotic PtK1 cells. Fluorescent EB1, which localized to polymerizing ends of astral and spindle microtubules, was used to track their polymerization. EB1 also associated with a subset of attached kinetochores in late prometaphase and metaphase, and rarely in anaphase. Localization occurred in a narrow crescent, concave toward the centromere, consistent with targeting to the microtubule plus end–kinetochore interface. EB1 did not localize to kinetochores lacking attached kinetochore microtubules in prophase or early prometaphase, or upon nocodazole treatment. By time lapse, EB1 specifically targeted to kinetochores moving antipoleward, coupled to microtubule plus end polymerization, and not during plus end depolymerization. It localized independently of spindle bipolarity, the spindle checkpoint, and dynein/dynactin function. EB1 is the first protein whose targeting reflects kinetochore directionality, unlike other plus end tracking proteins that show enhanced kinetochore binding in the absence of microtubules. Our results suggest EB1 may modulate kinetochore microtubule polymerization and/or attachment.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=138635Documentos Relacionados
- The adenomatous polyposis coli-binding protein EB1 is associated with cytoplasmic and spindle microtubules
- EB1–Microtubule Interactions in Xenopus Egg Extracts: Role of EB1 in Microtubule Stabilization and Mechanisms of Targeting to Microtubules
- Interactions between EB1 and Microtubules: DRAMATIC EFFECT OF AFFINITY TAGS AND EVIDENCE FOR COOPERATIVE BEHAVIOR*
- Transcriptional interference between the EBV transcription factors EB1 and R: both DNA-binding and activation domains of EB1 are required.
- Theoretical problems related to the attachment of microtubules to kinetochores.