title: Drosophilacanopy b is a cochaperone of glycoprotein 93.
abstract: Drosophilagp93 was identified as the ortholog of the mammalian endoplasmic reticulum-resident chaperone gp96. gp93 was found capable of rescuing gp96 client proteins, such as Toll-like receptors (TLRs) and integrins, in a gp96-deficient murine cell line. Mammalian gp96 was further found to require the cochaperone canopy 3 (CNPY3) for proper folding and expression of TLRs, but not integrins. InDrosophila, two possible CNPY family members have been identified but have not yet been characterized. Therefore, we sought to determine the role ofDrosophilaCNPYa and CNPYb in gp93 biology. Because of higher similarities between CNPY3 and CNPYb, we postulated that CNPYb would be a TLR-specific cochaperone of gp93. Indeed, CNPYb addition in gp93-expressing cells improved TLR expression. CNPYb and gp93 were further found to physically interact. Mutational analysis of cysteine residues in CNPYb identified differential dependence of these cysteines in chaperone function. Our study is the first to characterizeDrosophilaCNPY molecules. We further uncover more gp93 biology by identifying CNPYb as a cochaperone. A better understanding of this simplerDrosophilasystem will enable application to the mammalian system, such as has been done withEscherichia coli, yeast, and mammalian HSP90.
authors.affiliation: From the Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425 and.|the Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut 06030.
authors.forename: Crystal
authors.initials: C
authors.lastname: Morales
authors.affiliation: From the Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425 and zihai@musc.edu.
authors.forename: Zihai
authors.initials: Z
authors.lastname: Li
mesh_terms: D000818:Animals; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry; D004252:DNA Mutational Analysis; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D055503:Protein Multimerization; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D018841:HSP90 Heat-Shock Proteins; D018832:Molecular Chaperones; D012333:RNA, Messenger; D051193:Toll-Like Receptors; C544686:glycoprotein 93, Drosophila; D049452:Green Fluorescent Proteins; D003545:Cysteine
keywords: Drosophila; chaperone; gp93; gp96; innate immunity; integrin; protein folding; toll receptor; toll-like receptor (TLR)