scholarly journals ARFRP1 functions upstream of ARL1 and ARL5 to coordinate recruitment of distinct tethering factors to the trans-Golgi network

2019 ◽  
Vol 218 (11) ◽  
pp. 3681-3696 ◽  
Author(s):  
Morié Ishida ◽  
Juan S. Bonifacino
Keyword(s):  
Coiled Coil ◽  
Concerted Action ◽  
Long Distance ◽  
Master Regulator ◽  
Trans Golgi Network ◽  
Golgi Network

SNARE-mediated fusion of endosome-derived transport carriers with the trans-Golgi network (TGN) depends on the concerted action of two types of tethering factors: long coiled-coil tethers of the golgin family, and the heterotetrameric complex GARP. Whereas the golgins mediate long-distance capture of the carriers, GARP promotes assembly of the SNAREs. It remains to be determined, however, how the functions of these tethering factors are coordinated. Herein we report that the ARF-like (ARL) GTPase ARFRP1 functions upstream of two other ARL GTPases, ARL1 and ARL5, which in turn recruit golgins and GARP, respectively, to the TGN. We also show that this mechanism is essential for the delivery of retrograde cargos to the TGN. Our findings thus demonstrate that ARFRP1 is a master regulator of retrograde-carrier tethering to the TGN. The coordinated recruitment of distinct tethering factors by a bifurcated GTPase cascade may be paradigmatic of other vesicular fusion events within the cell.

Expansion of the trans-Golgi network following activated collagen secretion is supported by a coiled–coil microtubule-bundling protein, p180, on the ER

2010 ◽  
Vol 316 (3) ◽  
pp. 329-340 ◽  
Author(s):  
Tomonori Ueno ◽  
Keiko Kaneko ◽  
Harutaka Katano ◽  
Yuko Sato ◽  
Ralph Mazitschek ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Trans Golgi Network ◽  
Collagen Secretion ◽  
Golgi Network

scholarly journals A Family of Proteins with γ-Adaptin and Vhs Domains That Facilitate Trafficking between the Trans-Golgi Network and the Vacuole/Lysosome

2000 ◽  
Vol 149 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Jennifer Hirst ◽  
Winnie W.Y. Lui ◽  
Nicholas A. Bright ◽  
Nicholas Totty ◽  
Matthew N.J. Seaman ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Coated Vesicles ◽  
Carboxypeptidase Y ◽  
Golgi Stack ◽  
Trans Golgi Network ◽  
Terminal Domain ◽  
Vhs Domain ◽  
Golgi Network ◽  
Terminal Domains

We have cloned and characterized members of a novel family of proteins, the GGAs. These proteins contain an NH2-terminal VHS domain, one or two coiled-coil domains, and a COOH-terminal domain homologous to the COOH-terminal “ear” domain of γ-adaptin. However, unlike γ-adaptin, the GGAs are not associated with clathrin-coated vesicles or with any of the components of the AP-1 complex. GGA1 and GGA2 are also not associated with each other, although they colocalize on perinuclear membranes. Immunogold EM shows that these membranes correspond to trans elements of the Golgi stack and the TGN. GST pulldown experiments indicate that the GGA COOH-terminal domains bind to a subset of the proteins that bind to the γ-adaptin COOH-terminal domain. In yeast there are two GGA genes. Deleting both of these genes results in missorting of the vacuolar enzyme carboxypeptidase Y, and the cells also have a defective vacuolar morphology phenotype. These results indicate that the function of the GGAs is to facilitate the trafficking of proteins between the TGN and the vacuole, or its mammalian equivalent, the lysosome.

scholarly journals The trans-Golgi network GRIP-domain proteins form α-helical homodimers

2005 ◽  
Vol 388 (3) ◽  
pp. 835-841 ◽  
Author(s):  
Michael R. LUKE ◽  
Fiona HOUGHTON ◽  
Matthew A. PERUGINI ◽  
Paul A. GLEESON
Keyword(s):  
Protein Interactions ◽  
Coiled Coil ◽  
Helical Structure ◽  
Cd Spectroscopy ◽  
Protein Protein Interactions ◽  
Yeast Two Hybrid ◽  
Trans Golgi Network ◽  
Heptad Repeats ◽  
Golgi Network ◽  
Two Hybrid

A recently described family of TGN (trans-Golgi network) proteins, all of which contain a GRIP domain targeting sequence, has been proposed to play a role in membrane transport. On the basis of the high content of heptad repeats, GRIP domain proteins are predicted to contain extensive coiled-coil regions that have the potential to mediate protein–protein interactions. Four mammalian GRIP domain proteins have been identified which are targeted to the TGN through their GRIP domains, namely p230, golgin-97, GCC88 and GCC185. In the present study, we have investigated the ability of the four mammalian GRIP domain proteins to interact. Using a combination of immunoprecipitation experiments of epitope-tagged GRIP domain proteins, cross-linking experiments and yeast two-hybrid interactions, we have established that the GRIP proteins can self-associate to form homodimers exclusively. Two-hybrid analysis indicated that the N- and C-terminal fragments of GCC88 can interact with themselves but not with each other, suggesting that the GRIP domain proteins form parallel coiled-coil dimers. Analysis of purified recombinant golgin-97 by CD spectroscopy indicated a 67% α-helical structure, consistent with a high content of coiled-coil sequences. These results support a model for GRIP domain proteins as extended rod-like homodimeric molecules. The formation of homodimers, but not heterodimers, indicates that each of the four mammalian TGN golgins has the potential to function independently.

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