High impact information on ARF1

• This study shows that coatomer couples sorting signal recognition to the GTP hydrolysis reaction on ARF1 [1].
• Unexpectedly, we find that the GTPgammaS-dependent activator of PI(4)P5Kalpha is the small G protein ADP-ribosylation factor (ARF) and that the activation strictly requires phosphatidic acid, the product of phospholipase D (PLD) [2].
• The coat proteins required for budding COP-coated vesicles from Golgi membranes, coatomer and ADP-ribosylation factor (ARF) protein, are shown to be required to reconstitute the orderly process of transport between Golgi cisternae in which fusion of transport vesicles begins only after budding ends [3].
• Partial purification yielded an approximately 60-kDa BFA-insensitive GEP that enhanced binding of ARF1 and ARF3 to Golgi membranes [4].
• In the presence of 0.6-0.8 mM MgCl2 and 1 mM EDTA, binding of guanosine 5'-[gamma[35S]thio]triphosphate ([35S]GTP gamma S) by ARF1 and ARF3 was equally high without and with GEP [4].

Biological context of ARF1

• Comparison of the cDNA-derived amino acid sequences of ARF to other GTP-binding proteins reveals a structural relationship between ARF and the ras family of proteins [5].
• RNA gel blots of poly(A)+ RNA indicate that only one ARF message size (900 and 2000 base pairs) is present in yeast and cows, respectively [5].
• An oligonucleotide probe based on the partial amino acid sequence was used to clone ARF from a bovine adrenal chromaffin cDNA library [5].
• The yeast (Saccharomyces cerevisiae) ARF gene was then cloned from a YCp50 genomic library by cross-species hybridization by using the coding region of the bovine gene [5].
• Aluminum fluoride acts on the reversibility of ARF1-dependent coat protein binding to Golgi membranes [6].

Anatomical context of ARF1

• At the trans-Golgi network, clathrin coats containing AP-1 adaptor complexes are formed in an ARF1-dependent manner, generating vesicles transporting cargo proteins to endosomes [7].
• GTPgammaS-stimulated lysis was reconstituted with ARF1 purified from bovine brain cytosol or recombinant ARF1 [8].
• We have used the reconstitution of transport vesicle formation on isolated Golgi membranes to characterize mechanisms of ARF1 regulated actin polymerization [9].
• These data imply that CaM stimulates the PLD activity of rabbit neutrophils in concert with ARF [10].
• To investigate the role of ARF in regulated exocytosis, we have examined its intracellular distribution in cultured chromaffin cells by subcellular fractionation and immunoreplica analysis [11].

Associations of ARF1 with chemical compounds

• AP-1 recruitment was found to be dependent on myristoylated ARF1, GTP or nonhydrolyzable GTP-analogs, tyrosine signals, and small amounts of phosphoinositides, most prominently phosphatidylinositol 4,5-bisphosphate, in the absence of any additional cytosolic or membrane bound proteins [7].
• The ADP-ribosylation factor (ARF) is a 21-kDa GTP-binding protein that serves as the cofactor in the cholera toxin-catalyzed activation of the stimulatory guanine nucleotide-binding protein of adenylate cyclase (Gs) [5].
• The retinal extract also stimulates guanosine 5'-3-O-(thio)-triphosphate (GTP gamma S) release from ARF1 in the presence of phospholipids, but in this case myristoylation of ARF is not required [12].
• Vesicle formation was stimulated by supplemented clathrin, but inhibited by brefeldin A, consistent with the involvement of ARF1 and a brefeldin-sensitive guanine nucleotide exchange factor [13].
• The role of the amino terminus in the actions of ADP-ribosylation factor 1 (ARF1) was examined by comparing wild type ARF1, a 13-residue NH2-terminal deletion mutant ([delta 13]ARF1), and a 17-residue NH2-terminal deletion mutant ([delta 17]ARF1) [14].

Other interactions of ARF1

• Using preparations of dispersed bovine parathyroid cells, we have investigated the effect of a 16-residue synthetic peptide, ARF-16, which corresponds to the N-terminus of the ADP-ribosylation factor, on the secretion of PTH [15].
• Isolation, cloning, and characterization of brefeldin A-inhibited guanine nucleotide-exchange protein for ADP-ribosylation factor [16].

Analytical, diagnostic and therapeutic context of ARF1

• The recombinant Arf1 was compared with purified bovine brain Arf and shown to be nearly identical with respect to immunoblotting, guanine nucleotide binding, GTP hydrolysis, and cholera toxin cofactor activities [17].

References