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  • ADP-ribosylation factor, a small GTP-binding protein, is required for binding of the coatomer protein beta-COP to Golgi membranes.

ADP-ribosylation factor, a small GTP-binding protein, is required for binding of the coatomer protein beta-COP to Golgi membranes.

Proceedings of the National Academy of Sciences of the United States of America (1992-07-15)
J G Donaldson, D Cassel, R A Kahn, R D Klausner
ABSTRACT

The coatomer is a cytosolic protein complex that reversibly associates with Golgi membranes and is implicated in modulating Golgi membrane transport. The association of beta-COP, a component of coatomer, with Golgi membranes is enhanced by guanosine 5'-[gamma-thio]triphosphate (GTP[gamma S]), a nonhydrolyzable analogue of GTP, and by a mixture of aluminum and fluoride ions (Al/F). Here we show that the ADP-ribosylation factor (ARF) is required for the binding of beta-COP. Thus, beta-COP contained in a coatomer fraction that has been resolved from ARF does not bind to Golgi membranes, whereas binding can be reconstituted by the addition of recombinant ARF. Furthermore, an N-terminal peptide of ARF, which blocks ARF binding to Golgi membranes, inhibits GTP[gamma S]- as well as the Al/F-enhanced binding of beta-COP. We show that Golgi coat protein binding involves a sequential reaction where an initial interaction of ARF and GTP[gamma S] with the membrane allows subsequent binding of beta-COP to take place in the absence of free ARF and GTP[gamma S]. The fungal metabolite brefeldin A, which is known to prevent the association of coat proteins with Golgi membrane, is shown to exert this effect by interfering with the initial ARF-membrane interaction step.

MATERIALS
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Brand
Product Description

Sigma-Aldrich
Adenosine 5′-triphosphate disodium salt hydrate, Grade I, ≥99%, from microbial
Sign Into View Organizational & Contract Pricing
SKUVendor SKUPack SizeAvailabilityPrice
13855-250MG250 mg
Ships in 14 days - from Aldrich Partner.
US$139.15
13855-500MG500 mg
Ships in 14 days - from Aldrich Partner.
US$200.10
13855-1G1 g
Ships in 14 days - from Aldrich Partner.
US$279.45

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