title: Co-translational function of Cosmc, core 1 synthase specific molecular chaperone, revealed by a cell-free translation system.
abstract: The core 1 structure of the mucin type O-glycan is synthesized by core 1 β1,3-galactosyltransferase (C1GalT). Core 1 synthase specific molecular chaperone (Cosmc), a molecular chaperone specific for C1GalT, is essential for the expression of functional C1GalT in mammalian cells. In this study, we have established a procedure for detecting the chaperone activity of Cosmc by using a wheat germ cell-free translation system. Active C1GalT was expressed following simultaneous translation with Cosmc or translation in the presence of recombinant Cosmc protein. Moreover, we show that recombinant Cosmc must be present during the translation of C1GalT, as it is ineffective when added after translation. These results indicate that Cosmc mediates the co-translational activation of C1GalT and that it may prevent the unfavorable aggregation of C1GalT.
authors.affiliation: Glycogene Function Team of Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan. h.narimatsu@aist.go.jp
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Narimatsu
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kubota
authors.forename: Sanae
authors.initials: S
authors.lastname: Furukawa
authors.forename: Mie
authors.initials: M
authors.lastname: Shimojima
authors.forename: Hiroko
authors.initials: H
authors.lastname: Iwasaki
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Tozawa
authors.forename: Kouichi
authors.initials: K
authors.lastname: Tachibana
authors.forename: Hisashi
authors.initials: H
authors.lastname: Narimatsu
mesh_terms: D055162:Biocatalysis; D015153:Blotting, Western; D002474:Cell-Free System / Q000378:metabolism*; D005700:Galactosyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006603:Hexuronic Acids / Q000378:metabolism; D006801:Humans; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D058849:Protein Refolding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D014908:Triticum / Q000737:chemistry
chemical_list: C505369:C1GALT1C1 protein, human; D006603:Hexuronic Acids; D018832:Molecular Chaperones; D011994:Recombinant Proteins; C065803:N-acetylgalactosaminuronic acid; C505293:C1GALT1 protein, human; D005700:Galactosyltransferases