In molecular biology, the arfaptin domain is a protein domain which interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

s with ARF1

ARF1

ADP-ribosylation factor 1 is a protein that in humans is encoded by the ARF1 gene.-Interactions:ARF1 has been shown to interact with GGA3, PLD2, COPB1 and Muscarinic acetylcholine receptor M3.-Further reading:...

, a small GTPase involved in vesicle

Vesicle (biology)

A vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of many different molecules. More technically, a vesicle is a small membrane-enclosed sack that can store or transport substances. Vesicles can form naturally because of the properties of lipid membranes , or...

 budding

Budding

Budding is a form of asexual reproduction in which a new organism grows on another one. The new organism remains attached as it grows, separating from the parent organism only when it is mature. Since the reproduction is asexual, the newly created organism is a clone and is genetically identical...

 at the Golgi complex

Protein complex

A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...

 and immature secretory granules. The structure

Secondary structure

In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

 of arfaptin shows that upon binding

Binding (molecular)

Molecular binding is an attractive interaction between two molecules which results in a stable association in which the molecules are in close proximity to each other...

 to a small GTPase, arfaptin forms an elongated, crescent-shaped dimer

Protein dimer

In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...

 of three-helix coiled-coil

Coiled coil

A coiled coil is a structural motif in proteins, in which 2-7 alpha-helices are coiled together like the strands of a rope . Many coiled coil type proteins are involved in important biological functions such as the regulation of gene expression e.g. transcription factors...

s. The N-terminal region of ICA69 is similar to arfaptin.