Involved in GBF1 recruitment, Golgi maintenance and protein secretion. Interacts with PI4KB. Interacts with GBF1. The majority of ARMD3 is cytosolic, with a portion colocalizing with GBF1 at juxtanuclear Golgi sites. Belongs to the ARMH3 family. Contaminating sequence. Sequence of unknown origin in the N-terminal part.