| First Author | Hata S | Year | 2006 |
| Journal | J Biol Chem | Volume | 281 |
| Issue | 16 | Pages | 11214-24 |
| PubMed ID | 16476741 | Mgi Jnum | J:112682 |
| Mgi Id | MGI:3663188 | Doi | 10.1074/jbc.M509244200 |
| Citation | Hata S, et al. (2006) Stomach-specific calpain, nCL-2, localizes in mucus cells and proteolyzes the beta-subunit of coatomer complex, beta-COP. J Biol Chem 281(16):11214-24 |
| abstractText | Calpain is a Ca2+-regulated cytosolic protease. Mammals have 14 calpain genes, half of which are predominantly expressed in specific organ(s); the rest are expressed ubiquitously. A defect in calpains causes lethality/pathogenicity, indicating their physiological indispensability. nCL-2/calpain-8a was identified as a stomach-specific calpain, whose physiological functions are unclear. To elucidate these, we characterized nCL-2 in detail. Unexpectedly, nCL-2 was localized strictly to the surface mucus cells in the gastric epithelium and the mucus-secreting goblet cells in the duodenum. Yeast two-hybrid screening identified several nCL-2-interacting molecules. Of these, the beta-subunit of coatomer complex (beta-COP) occurs in the stomach pit cells and is proteolyzed by nCL-2 in vitro. Furthermore, beta-COP and nCL-2 co-expressed in COS7 cells co-localized in the Golgi, and Ca2+-ionophore stimulation caused the proteolysis of beta-COP near the linker region, resulting in the dissociation of beta-COP from the Golgi. These results strongly suggest novel functions for nCL-2 that involve the membrane trafficking of mucus cells via interactions with coat protein. |
