Intestinal MUC2 Mucin Supramolecular Topology by Packing and Release Resting on D3 Domain Assembly
2014 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 426, no 14, 2567-2579 p.Article in journal (Refereed) Published
MUC2 is the major gel-forming mucin of the colon forming a protective gel barrier organized into an inner stratified and an outer loose layer. The MUC2 N-terminus (D1-D2-D'D3 domains) has a dual function in building a net-like structure by disulfide-bonded trimerization and packing the MUC2 polymer into an N-terminal concatenated polygonal platform with the C-termini extending perpendicularly by pH- and calcium-dependent interactions. We studied the N-terminal D'D3 domain by producing three recombinant variants, with or without Myc tag and GFP (green fluorescent protein), and analyzed these by gel filtration, electron microscopy and single particle image processing. The three variants were all trimers when analyzed upon denaturing conditions but eluted as hexanners upon gel filtration under native conditions. Studies by electron microscopy and three-dimensional maps revealed cage-like structures with 2- and 3-fold symmetries. The structure of the MUC2 D3 domain confirms that the MUC2 mucin forms branched net-like structures. This suggests that the MUC2 mucin is stored with two N-terminal concatenated ring platforms turned by 180 against each other, implicating that every second unfolded MUC2 net in mature mucus is turned upside down.
Place, publisher, year, edition, pages
2014. Vol. 426, no 14, 2567-2579 p.
Von-Willebrand-Factor, Electron-Microscope Images, Polyacrylamide Gels, Terminus, Proteins, Secretion, Crystals, Sequence, Layers, Cells
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:kth:diva-149204DOI: 10.1016/j.jmb.2014.04.027ISI: 000339037700004ScopusID: 2-s2.0-84903179661OAI: oai:DiVA.org:kth-149204DiVA: diva2:738773
FunderSwedish Research CouncilSwedish Cancer SocietyKnut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research
QC 201408192014-08-192014-08-182014-08-19Bibliographically approved