About ADP-Ribosylation Factor / ARF:
ADP-Ribosylation factor proteins are small, binding proteins that belong to the ARF family of GTP-binding proteins. They are believed to function in diverse molecular activities, and they also play a role in conferring biotic as well as abiotic stresses in some species of plants. Because of their relation to the ARF family of proteins, ADP-ribosylation is typically associated with two different types of proteins; they are GTP/GDP exchange proteins, and other proteins.
GTP/GDP proteins Function
ARF binds to two different types of proteins, and they are guanosine triphosphate (GTP) and guanosine diphosphate (GDP). Assistance from other proteins is necessary in order for it to switch between GDP and GTP. The shape of the molecule is also dependent upon what form it is bound to.
Other proteins Mechanism
Other proteins may also react to ARF, and this depends largely on whether it is bound to GDP or GTP, and this certainly makes a big difference. The active form, ARF/GTP binds to vesicle coat proteins and adaptors, while the inactive form binds to transmembrane proteins and nothing more.
ADP-Ribosylation Factor Structure
The structure of ARFs is small proteins that are approximately 12 daltons in size, and contain two regions allowing them to switch between GDP and GTP. One of the things worth remembering is that ADP-ribosylation is physically associated with the Golgi complex.