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Curr Biol. 2009 Feb 10;19(3):196-205. doi: 10.1016/j.cub.2008.12.047. Epub 2009 Jan 29.

Motor- and tail-dependent targeting of dynein to microtubule plus ends and the cell cortex.

Author information

1
Biology Department, University of Massachusetts at Amherst, Amherst, MA 01003, USA.

Abstract

BACKGROUND:

Cytoplasmic dynein mediates spindle positioning in budding yeast by powering sliding of microtubules along the cell cortex. Although previous studies have demonstrated cortical and plus-end targeting of dynein heavy chain (Dyn1/HC), the regulation of its recruitment to these sites remains elusive.

RESULTS:

Here we show that separate domains of Dyn1/HC confer differential localization to the dynein complex. The N-terminal tail domain targets Dyn1/HC to cortical Num1 receptor sites, whereas the C-terminal motor domain targets Dyn1/HC to microtubule plus ends in a Bik1/CLIP-170- and Pac1/LIS1-dependent manner. Surprisingly, the isolated motor domain blocks plus-end targeting of Dyn1/HC, leading to a dominant-negative effect on dynein function. Overexpression of Pac1/LIS1, but not Bik1/CLIP-170, rescues the dominant negativity by restoring Dyn1/HC to plus ends. In contrast, the isolated tail domain has no inhibitory effect on Dyn1/HC targeting and function. However, cortical targeting of the tail construct is more robust than full-length Dyn1/HC and occurs independently of Bik1/CLIP-170 or Pac1/LIS1.

CONCLUSIONS:

Our results suggest that the cortical association domain is normally masked in the full-length dynein molecule. We propose that targeting of dynein to plus ends unmasks the tail, priming the motor for off-loading to cortical Num1 sites.

PMID:
19185494
PMCID:
PMC2674299
DOI:
10.1016/j.cub.2008.12.047
[Indexed for MEDLINE]
Free PMC Article
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