Rab6 Regulates Transport and Targeting of Exocytotic Carriers

Abstract

Constitutive exocytosis delivers newly synthesized proteins, lipids, and other molecules from the Golgi apparatus to the cell surface. This process is mediated by vesicles, which bud off the trans-Golgi network, move along cytoskeletal filaments, and fuse with the plasma membrane. Here, we show that the small GTPase Rab6 marks exocytotic vesicles and, together with the microtubule plus-end-directed motor kinesin-1, stimulates their processive microtubule-based transport to the cell periphery. Furthermore, Rab6 directs targeting of secretory vesicles to plasma-membrane sites enriched in the cortical protein ELKS, a known Rab6 binding partner. Our data demonstrate that although Rab6 is not essential for secretion, it controls the organization of exocytosis within the cellular space.

A New Vesicular Scaffolding Complex Mediates the G-Protein-Coupled 5-HT1AReceptor Targeting to Neuronal Dendrites

“…In agreement with these data, we found Rab6 labeling on the Golgi in the soma (Fig. 4 A3) and on vesicles in axons, compatible with its role in secretion (Grigoriev et al, 2007). Here, in addition, we visualized a clear labeling and trafficking in dendrites, suggesting that Rab6 also plays a role in the dendritic traffic (Fig.…”

“…Previous studies showed that Rab6 may interact ei- ther with a plus end-directed Kif5B (Grigoriev et al, 2007) or with a minus end-directed dynein (Wanschers et al, 2008). This led us to investigate their eventual interaction with the 5-HT 1A R.…”

“…Data are presented as real-time graphs of RU against time. (Grigoriev et al, 2007) and retrograde traffic (White et al, 1999;Del Nery et al, 2006) of vesicles from the Golgi that has also been shown to participate in the membrane targeting of some GPCRs (Deretic, 1997;Dong and Wu, 2007). But, to date, no data are available on its implication in the neuronal traffic of receptors.…”

Talin-KANK1 interaction controls the recruitment of cortical microtubule stabilizing complexes to focal adhesions

“…Other components of the same cortical assembly are the scaffolding proteins liprin-a1 and b1, a coiled-coil adaptor ELKS/ERC1, and the kinesin-4 KIF21A (Lansbergen et al, 2006;van der Vaart et al, 2013). Both liprins and ELKS are best known for their role in organizing presynaptic secretory sites (Hida and Ohtsuka, 2010;Spangler and Hoogenraad, 2007); in agreement with this function, ELKS is required for efficient constitutive exocytosis in HeLa cells (Grigoriev et al, 2007(Grigoriev et al, , 2011. LL5b, liprins and ELKS form micrometer-sized cortical patch-like structures, which will be termed here cortical microtubule stabilization complexes, or CMSCs.…”

Regulation of β2-Adrenergic Receptor Maturation and Anterograde Trafficking by an Interaction with Rab Geranylgeranyltransferase

“…To cite a few, transport between the ER and Golgi complex is regulated by Rab1 and Rab2 which orchestrate specificity in fusion with membranes at the cisGolgi (4 -6). At the level of the Golgi complex, Rab6a regulates trafficking in both a retrograde (from early endosomes and Golgi to the ER) and an anterograde (from the Golgi to the plasma membrane) direction (7)(8)(9)(10)(11)(12)(13). Transport from the Golgi to the plasma membrane can follow several paths.…”