F-actin regulator involved in anterograde Golgi to endosome transport: upon ubiquitination via 'Lys-33'-linked ubiquitin chains by the BCR(KLHL20) E3 ubiquitin ligase complex, interacts with EPS15 and localizes to the trans-Golgi network, where it promotes actin polymerization, thereby facilitating post-Golgi trafficking. May play a role in the maintenance of the Golgi apparatus morphology (By similarity). Interacts with clathrin adapter AP1 complex. This interaction takes place at Golgi membranes and not AP1-positive endosomal membranes. Interacts (when ubiquitinated at Lys-469) with EPS15 (By similarity). Predominantly cytosolic. Detected on vesicle-like cytoplasmic structures and on the cis-Golgi. Not associated with actin filaments. In the adult, widely expressed with highest levels in brain, thymus and kidney and low levels in skeletal and heart muscle. Not expressed in lung. In the eye, strongly expressed in the outer plexiform layer of the retina. In the intestine, expressed both in terminally differentiated epithelial cells and in crypt epithelium. In the embryo, strongest expression is seen in brain, thymus, intestine, apical epidermal layers of the skin and developing lens fibers of the eye. In the embryo, expressed from 5 dpc and levels increase strongly until 15 dpc. The membrane-associated form is phosphorylated on tyrosine residues. Ubiquitinated via 'Lys-33'-linked ubiquitin chains by the BCR(KLHL20) E3 ubiquitin ligase complex: 'Lys-33'-linked ubiquitination promotes interaction with EPS15 and facilitates actin polymerization at the trans-Golgi network, thereby facilitating post-Golgi trafficking. Deubiquitinated by ZRANB1/TRABID (By similarity). Belongs to the WD repeat coronin family.