Cell Biology

Roping in Rabs

See allHide authors and affiliations

Science  05 Dec 2008:
Vol. 322, Issue 5907, pp. 1439
DOI: 10.1126/science.322.5907.1439b

The Golgi apparatus receives vesicles and other membrane-bound carriers from earlier compartments of the secretory pathway and must guide them to the correct cisternae within the Golgi stack. At the same time, it must exclude other large structures such as ribosomes. Sinka et al. suggest that coiled-coil domains, termed golgins, which localize to particular Golgi subdomains through their C termini, might play a role in vesicle sorting. They found that the GRIP domain golgins in Drosophila bind members of the Rab family of G proteins through binding sites organized along the length of their coiled-coil domains. A single Rab showed binding to multiple GRIP domain proteins and a single golgin coiled-coil domain bound more than one Rab. They suggest that the golgins form an array that surrounds the Golgi with the coiled-coils projecting into the cytoplasm like tentacles. The tentacles might capture Rab-bearing membranes but exclude structures such as ribosomes that lack Rabs. Different binding specificities may both influence the localization of initial capture and allow iterative binding and release in order to move captured membranes to the appropriate Golgi subdomain. This scheme would be analogous to the proposal for the nuclear pore in which importins are moved through the pore by binding to a gel of phenylalanine-glycine repeats formed by nuclear porins. — VV

J. Cell. Biol. 183, 607 (2008).

Navigate This Article