Required for normal Golgi function (PubMed:18422605). Necessary for embryo development and pigmentation, especially for the expansion of cells and organs, and for the formation of the organized shoot apical meristem (SAM) (PubMed:18422605). Probably involved in the generation of the extra-cellular matrix (PubMed:18422605). Component of the conserved oligomeric Golgi complex which is composed of eight different subunits and is required for normal Golgi morphology and localization (Probable). Interacts with COG5 and COG6 (PubMed:27448097). Abnormal coloration and morphology of embryos leading to bushy plants, with aberrant organization of the shoot apical meristem (SAM) and unexpanded leaves with irregular phyllotaxy, as well as small and round epidermal cells (PubMed:18422605). Disrupted hydrophobic layers of epidermal cells (PubMed:18422605). Mislocalization of Golgi proteins (e.g. ERD2) and altered size of the Golgi apparatus (PubMed:18422605). Belongs to the COG7 family.