Coatomer subunit alpha
Developmental stage
Xenin is released into the circulation after a meal.
Function
The 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 (By similarity).
Xenin stimulates exocrine pancreatic secretion. It inhibits pentagastrin-stimulated secretion of acid, to induce exocrine pancreatic secretion and to affect small and large intestinal motility. In the gut, xenin interacts with the neurotensin receptor.
Involvement in disease
Autoimmune interstitial lung, joint, and kidney disease
AILJK
An autoimmune disease characterized by inflammatory arthritis, interstitial lung disease, and immune complex-mediated renal disease.
None
The disease is caused by variants affecting the gene represented in this entry.
Tissue Specificity
Uniformly expressed in a wide range of adult and fetal tissues. Xenin is found in gastric, duodenal and jejunal mucosa. Circulates in the blood. Seems to be confined to specific endocrine cells.
Cellular localization
- Cytoplasm
- Golgi apparatus membrane
- Peripheral membrane protein
- Cytoplasmic side
- Cytoplasmic vesicle
- COPI-coated vesicle membrane
- Peripheral membrane protein
- Cytoplasmic side
- The coatomer is cytoplasmic or polymerized on the cytoplasmic side of the Golgi, as well as on the vesicles/buds originating from it.
- Xenin
- Secreted
Alternative names
Coatomer subunit alpha, Alpha-coat protein, HEP-COP, Alpha-COP, HEPCOP, COPA