A post-translational modification of proteins by the addition of the ADP-ribosyl moiety of NAD. It is a normal regulatory mechanism but is also the way in which several AB toxins have their effects. ADP-ribosylation factor (ARF) is an ubiquitous GTP-binding protein (181 aa) that mediates the binding of non-clathrin coated vesicles and AP1 (adaptor-protein 1) of clathrin-coated vesicles to Golgi membranes. At least six isoforms have been identified. It is also an allosteric activator of the cholera toxin catalytic subunit. ADP-ribosylation factor-binding proteins (Golgi-associated γ-adaptin ear containing ARF-binding proteins, GGAs 1–3, 639 aa, 613 aa, and 723 aa respectively) mediate the ARF-dependent recruitment of clathrin to the trans-Golgi network.
Subjects: Chemistry — Medicine and Health.