The GRAB (GRIP-related Arf-binding) domain is towards the C-terminus of Rud3 type proteins. This domain is related to the GRIP domain, but the conserved tyrosine residue found at position 4 in all GRIP domains is replaced by a leucine residue. The Arf small GTPase is localised to the cis-Golgi where it recruits proteins via their GRAB domain, as part of the transport of cargo from the endoplasmic reticulum to the plasma membrane [1].

1: Role of tethering factors in secretory membrane traffic. Sztul E, Lupashin V; Am J Physiol Cell Physiol. 2006;290:11-26. PMID:16338975

2: The GTPase Arf1p and the ER to Golgi cargo receptor Erv14p cooperate to recruit the golgin Rud3p to the cis-Golgi. Gillingham AK, Tong AH, Boone C, Munro S; J Cell Biol. 2004;167:281-292. PMID:15504911