FunctionThe coatomer is a cytosolic protein complex that binds to dilysine motifs and reversibly associates with Golgi non-clathrin-coated vesicles, which further mediate biosynthetic protein transport from the ER, via the Golgi up to the trans Golgi network. Coatomer complex is required for budding from Golgi membranes, and is essential for the retrograde Golgi-to-ER transport of dilysine-tagged proteins. In mammals, the coatomer can only be recruited by membranes associated to ADP-ribosylation factors (ARFs), which are small GTP-binding proteins; the complex also influences the Golgi structural integrity, as well as the processing, activity, and endocytic recycling of LDL receptors.
Tissue specificityUbiquitously expressed.
Sequence similaritiesBelongs to the adaptor complexes medium subunit family. Delta-COP subfamily. Contains 1 MHD (mu homology) domain.
Cellular localizationCytoplasm. Golgi apparatus membrane. Cytoplasmic vesicle > COPI-coated vesicle membrane. The coatomer is cytoplasmic or polymerized on the cytoplasmic side of the Golgi, as well as on the vesicles/buds originating from it.
Zhang X et al. Dopamine receptor D3 regulates endocytic sorting by a Prazosin-sensitive interaction with the coatomer COPI. Proc Natl Acad Sci U S A109:12485-90 (2012).
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