The COG complex comprises eight proteins (COG1-8) and plays critical roles in Golgi structure and function. It is necessary for retrograde trafficking in the Golgi apparatus and for protein glycosylation [, ]. COG complex, together with exocyst, Golgi-associated retrograde protein (GARP) and Dsl1 complexes, is a member of the CATHR (complexes associated with tethering containing helical rods) family sharing an evolutionary origin and structural features []. This domain is found in the C-terminal of COG complex subunit 2 proteins and consists of a conserved α-helical bundle. In Arabidopsis, COG2 forms a complex with FPP3/VETH1 and FPP2/VETH2 and ensures the correct secondary cell wall (SCW) deposition pattern by recruiting exocyst components to cortical microtubules in xylem cells during secondary cell wall deposition [].
