ADP Ribosylation Factor Interacting Protein 1 (ARFIP1)

Sequence analysis predicted that the 341-amino acid arfaptin-1 protein, which is 60% identical to arfaptin-2, contains a leucine zipper motif, which is interrupted with a met at position 157, and several potential phosphorylation sites.

In vitro binding analysis showed that arfaptin-1 binds to nonmyristoylated GTP-bound ARF3, but not to GDP-bound ARF3, and also to ARF1, another class I ARF. It binds with lower affinity to ARF5, a class II ARF, and with very little affinity to ARF6 , a class III ARF. Immunoblot analysis indicated that arfaptin-1 is recruited from the cytosol to Golgi membranes by ARFs in a guanosine 5-prime-O-(3-thiotriphosphate)-dependent and brefeldin A-sensitive manner but is not a constituent of coatomer .