Calnexin, a type I integral Ca2+-binding protein in the endoplasmic reticulum (ER) membrane, has been implicated in various biological functions including chaperone activity, calcium homeostasis, phagocytosis, and ER stress-induced apoptosis. Caenorhabditis elegans CNX-1 is expressed in the H-shaped excretory cell, intestine, dorsal and ventral nerve cord, spermatheca, and head and tail neurons throughout development. A cnx-1 null mutant displays temperature-sensitive developmental and reproductive defects, and retarded growth under stress. Moreover, a double knockout mutant of calnexin and calreticulin exhibits additive severe defects. Interestingly, both cnx-1 transcript and protein levels are elevated under stress conditions suggesting that CNX-1 may be important for stress-induced chaperoning functions in C. elegans. Glycosidase treatment and site-directed mutagenesis confirmed that CeCNX-1 is N-glycosylated at two asparagine residues of Asn203 and Asn571. When transgenic animals from cnx-1 mutant were generated, a glycosylation defective construct failed to rescue phenotypes of cnx-1 mutant suggesting that glycosylation is important for calnexin's functions in C. elegans.
|Number of pages||13|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 2005 Dec 16|
Bibliographical noteFunding Information:
We thank A. Coulson for cosmids, the CGC for worm strains, A. Fire for expression vectors, and Y. Kohara for yk clones. We are especially grateful to C. Johnson for giving strains, L. Vanoaica for manuscript preparation, and M. Kim for computing 3D structure of CeCNX-1. This work was supported by the grant (M103KV010019-04K2201-01920) from the Korea Ministry of Science and Technology.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology