MOBILE BUILDERS: Proteins called EB1 comets (green) that bind to microtubules (blue) are often found at the same site as Golgi outposts (red) (1). Golgi outposts can make microtubules in vitro, with two proteins—γ-tubulin and CP309—essential for the process (2). EB1s were also seen growing from Golgi outposts at the tips of dendrites, suggesting Golgi outposts generate fresh microtubules on which new branches form (3).PRECISION GRAPHICS
The paper
K.M. Ori-McKenney et al., “Golgi outposts shape dendrite morphology by functioning as sites of acentrosomal microtubule nucleation in neurons,” Neuron, 76:921-30, 2012.
In neurons, microtubules are essential for generating the axonal and dendritic extensions that carry electrical impulses. In most cells, these cylindrical polymers of tubulin grow from centrosomes, but in neurons, centrosomes lose function as the cells develop, suggesting another point of origin for this essential structural protein.
Some researchers have proposed that in dendrites, the job might be carried out by Golgi outposts—smaller Golgi-type structures that move to dendritic branch points and tips, extending the function of the main Golgi apparatus, which acts as both manufacturer and courier of many macromolecules. To test the idea, Kassandra Ori-McKenney and colleagues at the ...
