|Protein Name||ADP-ribosylation factor 1|
|Milk Fraction||MFGM, Exosome|
|Ref Sequence Id||NP_788826.1|
|Amino Acid Lenth||181|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Presence in other biological fluids/tissue/cells||localized to the Golgi apparatu; found in every eukaryotic cell; present in high abundance (-1% of cell protein) in brain tissue; highly enriched in coated vesicles as compared with parental Golgi cisternae|
|Protein Function||Arf family of GTP-binding (G) proteins, including the Arf-like (Arl) proteins and Sar1, regulate membrane traffic and organelle structure through the membrane recruitment of cargo-sorting coat proteins; and interacts with regulators of other G proteins; activity of the ADP-ribosylation factor (ARF) is that of a cofactor, which is in turn regulated by GTP; may modulate vesicle budding and uncoating through controlled GTP hydrolysis; Arfs have several important functions, including the recruitment of coat proteins that promote sorting of cargo into vesicles, the recruitment and activation of enzymes such as the phosphatidylinositol kinases that alter membrane lipid composition, and interaction with cytoskeletal factors; Arfs can also recruit and activate enzymes that alter membrane lipid composition|
|Biochemical Properties||ARF and ARLs function is under tight spatial control, mediated by guanine nucleotide-exchange factors (GEFs) and GTPase activating proteins (GAPs) that catalyse GTP exchange and hydrolysis; Asp-26 of ARF corresponds to Gly-12 of ras proteins, which is an important determinant of GTPase activity and transformation potency- lack of a glycine at this position may explain the lack of GTPase activity of purified ARF; ARF, as purified from cytosol, is accompanied by a bound GDP molecule and has no measurable GTPase activity (upper estimate of 0.0015/min), nor will it readily exchange GTP for endogenous GDP- However, exchange can be accomplished under conditions of high ionic strength or denaturation/renaturation|
|PTMs||all Arf proteins are myristoylated at the amino terminus-consensus sequence for aminoterminal myristoylation (Metiit-Gly-Xaa-Xaa-Xaa-Ser/Ala/ Thr); Some Arl proteins are myristoylated but most appear to lack this modification|
|Significance of PTMs||This cotranslational modification is required for membrane recruitment and biological activity|
|PDB ID||1R8Q, 1R8S, 1S9D, 4C0A,|
|Bibliography||1. Sewell, J. L. and Kahn, R. A. (1988) ‘Sequences of the bovine and yeast ADP-ribosylation factor and comparison to other GTP-binding proteins.’, Proceedings of the National Academy of Sciences of the United States of America, 85(13), pp. 4620–4. doi: 10.1073/pnas.85.13.4620. |
2. Stearns, T. et al. (1990) ‘ADP-ribosylation factor is functionally and physically associated with the Golgi complex.’, Proceedings of the National Academy of Sciences, 87(3), pp. 1238–1242. doi: 10.1073/pnas.87.3.1238.
3. Serafini, T. et al. (1991) ‘ADP-ribosylation factor is a subunit of the coat of Golgi-derived COP-coated vesicles: a novel role for a GTP-binding protein.’, Cell, 67(2), pp. 239–53. doi: 10.1016/0092-8674(91)90176-y.