Dynein's role in yeast mitosis
Dynein is a large molecular motor that transports cargo along microtubules in the cell. Unlike kinesins, which travel towards the fast-growing plus end of the microtubule, dynein "walks" in the minus end direction. Dyneins are classified as belonging to one of two groups: axonemal (or flagellar) dynein, which is a component of cilia and flagella, and cytoplasmic dynein.
In the budding yeast Saccharomyces cerevisiae, dynein plays a critical role in positioning the mitotic spindle during mitosis. At metaphase, dynein is localized the spindle pole body (shown in orange in the animation) of the daughter cell, and is eventually targeted towards the plus end of an astral microtubule. When the astral microtubule plus end encounters a target at the bud cortex (which includes the protein Num1), dynein is transferred from the microtubule to the cortical target (shown in red) and becomes active (indicated by the change in color from black to green). The activated dynein, which is anchored to the cortex, pulls the microtubule towards the bud cortex, causing the mitotic spindle to move into the bud neck.
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Many thanks to Sam Reck-Peterson (Harvard Medical School) for collaborating on this project.