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dc.contributor.authorEhrencrona, Erik
dc.date.accessioned2021-10-26T11:05:05Z
dc.date.available2021-10-26T11:05:05Z
dc.date.issued2021-10-26
dc.identifier.isbn978-91-8009-468-9 (PRINT)
dc.identifier.isbn978-91-8009-469-6 (PDF)
dc.identifier.urihttp://hdl.handle.net/2077/69314
dc.description.abstractIn this thesis, a bottom-up approach was used to study the IgG Fc-binding protein (FCGBP), which next to the MUC2 mucin is the second main component of secreted mucus in small intestine and colon. FCGBP is also found in airways during inflammatory conditions with static mucus. Although discovered as an IgG sequesterer, this function was not reproducible here using purified proteins. FCGBP includes many von Willebrand D domains (vWDs) with most having a GDPH (Gly-Asp-Pro-His) motif. Theoretically, hydrolysis of the DP peptide bonds should result in reactive Asp-anhydrides driving covalent crosslinking between FCGBP and MUC2. Using mass spectrometry (MS), recombinant proteins, electrophoresis and Western blot, we found that all motifs were cleaved but FCGBP remained intact as consecutive fragments were tethered by single disulphide bonds. Label-free MS quantification of proteins in murine mucus showed that Muc2 and Fcgbp are mostly not covalently bound, and in silico structural predictions further argued against such interactions, with these Asp-anhydrides being inaccessible for their suggested MUC2 substrates. Recombinant proteins were purified, analysed and used for generation of FCGBP antisera. The murine Fcgbp is smaller but highly similar to the human orthologue, making it ideal for functional and structural studies. Microscopy was used to study live and fixed tissue from mouse colon and airways to investigate its physiological role. Recombinant proteins formed C-terminal cysteine dimers with cryogenic electron microscopy (cryo-EM) showing a spring feather-like quaternary structure. Even larger linear structures were detected in cryo-EM micrographs, and electrophoresis showed large complexes in mucus. Immunohistochemistry (IHC) also revealed elongated ultrastructures in healthy intestine and airways of a murine chronic obstructive pulmonary disease (COPD) model. Results indicated less attached mucus in airways of Fcgbp-/- mice, and further a mucus expansion phenotype in colon. An N-terminal sequence linked to helical gliding was studied and alignments revealed that the murine sequence had partially been genetically lost. The remaining N-terminal sequence shared between human and mouse was found to be repeated prior to every vWD in the FCGBP sequence. In summary, these results indicate a role for FCGBP in mucus structure and attachment.sv
dc.language.isoengsv
dc.relation.haspartI. Ehrencrona, E. van der Post, S. Gallego, P. Recktenwald, C. Rodriguez-Pineiro, A.M. Garcia-Bonete, MJ. Trillo-Muyo, S. Bäckström, M. Hansson, GC. Johanson, MEV. The IgGFc-binding protein FCGBP is secreted with all GDPH sequences cleaved but maintained by interfragment disulfide Bonds. Journal of Biochemistry 2021; 293(1):100871. ::doi::10.1016/j.jbc.2021.100871sv
dc.relation.haspartII. Fakih, D. Ehrencrona, E. Martinez-Abad, B. Arike, L., Ermund, A. Trillo-Muyo, S. Gallego, P. Johansson, M.E.V. and Hansson, G.C. The FCGBP Protein Induced at Lung Disease Anchors the Mucus Layer to the Airway Surface. Manuscript.sv
dc.relation.haspartIII. Ehrencrona, E*. Gallego, P*. Garcia-Bonete, M.J. Trillo-Muyo, S. van der Post, S.V.P. Recktenwald, C.V., Rodriguez-pineiro, A.M. Hansson, G.C. and Johansson, M.E.V. The FCGBP Structure Reveals a Convoluted C-terminal Dimer Stabilised by Cysteine Bonds. Manuscript. * Equal contributionsv
dc.relation.haspartIV. Ehrencrona, E. Svensson, F. Gallego, P. Garcia-Bonete, M.J. Martinez Abad, B. Hansson, G.C. Johansson, M.E.V. Functional Analyses of FCGBP and its Role in Organisation of the Colonic Mucus Barrier. Manuscript.sv
dc.subjectMucussv
dc.subjectFCGBPsv
dc.subjectIgGsv
dc.subjectIBDsv
dc.subjectCOPDsv
dc.subjectMucinssv
dc.subjectDisulphidesv
dc.subjectGDPHsv
dc.titleThe Role of FCGBP in Mucus - Structure, Processing and Functionsv
dc.typetexteng
dc.type.svepDoctoral thesiseng
dc.gup.mailerik.ehrencrona@medkem.gu.sesv
dc.type.degreeDoctor of Philosophy (Medicine)sv
dc.gup.adminSpikning Oktober 22, kl 11.00.sv
dc.gup.originUniversity of Gothenburg. Sahlgrenska Academysv
dc.gup.departmentInstitute of Biomedicine. Department of Medical Biochemistry and Cell Biologysv
dc.gup.defenceplaceFredagen den 12 november 2021, kl. 13.00, Arvid Carlson, Academicum, Medicinaregatan 3, Göteborg https://gu-se.zoom.us/j/67999054129?pwd=ajNqczAxb20wUWtqSEI3OHdscUM0Zz09sv
dc.gup.defencedate2021-11-12
dc.gup.dissdb-fakultetSA


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