Based on limited published evidence, ARMH3 is an armadillo-repeat protein involved in Golgi maintenance and protein secretion. It functions as an ARL5 effector recruited to the trans-Golgi network (TGN) through the SYS1-ARFRP1-ARL5 axis 1. ARMH3 activates phosphatidylinositol 4-kinase IIIβ (PI4KB) to generate phosphatidylinositol 4-phosphate (PI4P) at the TGN, facilitating GOLPH3 recruitment and glycan modifications 1. It localizes to the cytosol and Golgi membrane, binding to active ARL5 and regulating Golgi organization 1.