| Primary Identifier | IPR045872 | Type | Family |
| Short Name | Arf1-5-like |
| description | Arf GTPases are involved in the formation of coated carrier vesicles by recruiting coat proteins. This entry includes Arf1, Arf2, Arf3, Arf4, Arf5, and related proteins. Each contains an N-terminal myristoylated amphipathic helix that is folded into the protein in the GDP-bound state. GDP/GTP exchange exposes the helix, which anchors to the membrane. Following GTP hydrolysis, the helix dissociates from the membrane and folds back into the protein. A general feature of Arf1-5 signaling may be the cooperation of two Arfs at the same site. Arfs1-5 are generally considered to be interchangeable in function and location, but some specific functions have been assigned []. Arf1 localizes to the early/cis-Golgi, where it is activated by GBF1 and recruits the coat protein COPI. It also localizes to the trans-Golgi network (TGN), where it is activated by BIG1/BIG2 and recruits the AP1, AP3, AP4, and GGA proteins []. Humans, but not rodents and other lower eukaryotes, lack Arf2. Human Arf3 shares 96% sequence identity with Arf1 and is believed to generally function interchangeably with Arf1. Human Arf4 in the activated (GTP-bound) state has been shown to interact with the cytoplasmic domain of epidermal growth factor receptor (EGFR) and mediate the EGF-dependent activation of phospholipase D2 (PLD2), leading to activation of the activator protein 1 (AP-1) transcription factor []. Arf4 has also been shown to recognise the C-terminal sorting signal of rhodopsin and regulate its incorporation into specialised post-Golgi rhodopsin transport carriers (RTCs) []. There is some evidence that Arf5 functions at the early-Golgi and the trans-Golgi to affect Golgi-associated alpha-adaptin homology Arf-binding proteins (GGAs) []. |
