Stabilizing the microtubule scaffold

Combining stability with movement is a perpetual challenge for engineers. Linda Sandblad, Damian Brunner, Andreas Hoenger (EMBL, Heidelberg, Germany), and colleagues now report just such an engineering feat for a microtubule binding protein. Mal3p, they show, binds in such a way as to both stabilize microtubules and allow free-flowing transportation along their length.

Microtubules are not just the cell's scaffolding, they are also the highways for transporting factors and vesicles. To perform their various functions, microtubules interact with a number of motor proteins and other microtubule-associated proteins (MAPs), the most conserved of which are the end binding proteins, such as EB1.

Despite its name, the precise mode in which EB1 binds to microtubules was unknown. Light microscopy had revealed an accumulation of the yeast EB1 homologue, Mal3p, at the microtubule plus end,...