A distinct Golgi-targeting mechanism of dGM130 in Drosophila neurons

GM130 is a matrix protein that is conserved in metazoans and involved in the architecture of the Golgi apparatus. In neurons, Golgi apparatus and dendritic Golgi outposts (GOs) have different compartmental organizations, and GM130 localization is present in both, indicating that GM130 has a unique Golgi-targeting mechanism. Here, we investigated the Golgi-targeting mechanism of the GM130 homologue, dGM130, using in vivo imaging of Drosophila dendritic arborization (da) neurons. The results showed that two independent Golgi-targeting domains (GTDs) with different Golgi localization characteristics in dGM130, together determined the precise localization of dGM130 in both the soma and dendrites. GTD1, covering the first coiled-coil region, preferentially targeted to somal Golgi rather than GOs; whereas GTD2, containing the second coiled-coil region and C-terminus, dynamically targeted to Golgi in both soma and dendrites. These findings suggest that there are two distinct mechanisms by which dGM130 targets to the Golgi apparatus and GOs, underlying the structural differences between them, and further provides new insights into the formation of neuronal polarity.