A minus-end-directed kinesin with plus-end tracking protein activity is involved in spindle morphogenesis

Diverse kinesin motor proteins are involved in spindle function; however, the mechanisms by which they are targeted to specific sites within spindles are not well understood. Here, we show that a fusion between yellow fluorescent protein (YFP) and a minus-end-directed Kinesin-14 (C-terminal family)...

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Bibliographic Details
Published in:Molecular biology of the cell 2005-04, Vol.16 (4), p.1584-1592
Main Authors: Ambrose, J Christian, Li, Wuxing, Marcus, Adam, Ma, Hong, Cyr, Richard
Format: Article
Language:English
Subjects:
Arabidopsis - cytology
Arabidopsis - metabolism
Arabidopsis Proteins - chemistry
Arabidopsis Proteins - metabolism
Kinesin - chemistry
Kinesin - metabolism
Microtubules - metabolism
Spindle Apparatus - chemistry
Spindle Apparatus - metabolism
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Summary:Diverse kinesin motor proteins are involved in spindle function; however, the mechanisms by which they are targeted to specific sites within spindles are not well understood. Here, we show that a fusion between yellow fluorescent protein (YFP) and a minus-end-directed Kinesin-14 (C-terminal family) from Arabidopsis, ATK5, localizes to mitotic spindle midzones and regions rich in growing plus-ends within phragmoplasts. Notably, in Arabidopsis interphase cells, YFP::ATK5 localizes to microtubules with a preferential enrichment at growing plus-ends; indicating ATK5 is a plus-end tracking protein (+TIP). This +TIP activity is conferred by regions outside of the C-terminal motor domain, which reveals the presence of independent plus-end tracking and minus-end motor activities within ATK5. Furthermore, mitotic spindles of atk5 null mutant plants are abnormally broadened. Based on these data, we propose a model in which ATK5 uses plus-end tracking to reach spindle midzones, where it then organizes microtubules via minus-end-directed motor activity.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.E04-10-0935