title: Caenorhabditis elegans calnexin is N-glycosylated and required for stress response.
abstract: Calnexin, a type I integral Ca(2+)-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 Asn(203) and Asn(571). 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.
authors.affiliation: Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Wonhae
authors.initials: W
authors.lastname: Lee
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Lee
authors.forename: Byung-Jae
authors.initials: BJ
authors.lastname: Park
authors.forename: Jong-Wook
authors.initials: JW
authors.lastname: Chang
authors.forename: Jae-Ran
authors.initials: JR
authors.lastname: Yu
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Koo
authors.forename: Hyun
authors.initials: H
authors.lastname: Park
authors.forename: Yung Joon
authors.initials: YJ
authors.lastname: Yoo
authors.forename: Joohong
authors.initials: J
authors.lastname: Ahnn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D037281:Calnexin / Q000737:chemistry* / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006031:Glycosylation; D018869:Heat-Shock Response / Q000502:physiology*; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000502:physiology*; D013329:Structure-Activity Relationship
chemical_list: D037281:Calnexin