title: Maltose-Binding Protein (MBP), a Secretion-Enhancing Tag for Mammalian Protein Expression Systems.
abstract: Recombinant proteins are commonly expressed in eukaryotic expression systems to ensure the formation of disulfide bridges and proper glycosylation. Although many proteins can be expressed easily, some proteins, sub-domains, and mutant protein versions can cause problems. Here, we investigated expression levels of recombinant extracellular, intracellular as well as transmembrane proteins tethered to different polypeptides in mammalian cell lines. Strikingly, fusion of proteins to the prokaryotic maltose-binding protein (MBP) generally enhanced protein production. MBP fusion proteins consistently exhibited the most robust increase in protein production in comparison to commonly used tags, e.g., the Fc, Glutathione S-transferase (GST), SlyD, and serum albumin (ser alb) tag. Moreover, proteins tethered to MBP revealed reduced numbers of dying cells upon transient transfection. In contrast to the Fc tag, MBP is a stable monomer and does not promote protein aggregation. Therefore, the MBP tag does not induce artificial dimerization of tethered proteins and provides a beneficial fusion tag for binding as well as cell adhesion studies. Using MBP we were able to secret a disease causing laminin β2 mutant protein (congenital nephrotic syndrome), which is normally retained in the endoplasmic reticulum. In summary, this study establishes MBP as a versatile expression tag for protein production in eukaryotic expression systems.
authors.affiliation: Institute for Dental Research and Oral Musculoskeletal Biology, Medical Faculty, University of Cologne, Cologne, Germany.|Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Raphael
authors.initials: R
authors.lastname: Reuten
authors.affiliation: Institute for Dental Research and Oral Musculoskeletal Biology, Medical Faculty, University of Cologne, Cologne, Germany.|Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Denise
authors.initials: D
authors.lastname: Nikodemus
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Maria B
authors.initials: MB
authors.lastname: Oliveira
authors.affiliation: Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba RT3 2N2, Canada.|School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, United Kingdom.
authors.forename: Trushar R
authors.initials: TR
authors.lastname: Patel
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.|Experimental Neonatology, Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Bent
authors.initials: B
authors.lastname: Brachvogel
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Breloy
authors.affiliation: Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba RT3 2N2, Canada.
authors.forename: Jörg
authors.initials: J
authors.lastname: Stetefeld
authors.affiliation: Institute for Dental Research and Oral Musculoskeletal Biology, Medical Faculty, University of Cologne, Cologne, Germany.|Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.|Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Koch
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D015870:Gene Expression; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D058619:Maltose-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D058619:Maltose-Binding Proteins; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins