title: EMILIN-3, peculiar member of elastin microfibril interface-located protein (EMILIN) family, has distinct expression pattern, forms oligomeric assemblies, and serves as transforming growth factor β (TGF-β) antagonist.
abstract: EMILIN-3 is a glycoprotein of the extracellular matrix belonging to a family that contains a characteristic N-terminal cysteine-rich EMI domain. Currently, EMILIN-3 is the least characterized member of the elastin microfibril interface-located protein (EMILIN)/Multimerin family. Using RNA, immunohistochemical, and protein chemistry approaches, we carried out a detailed characterization of the expression and biochemical properties of EMILIN-3 in mouse. During embryonic and postnatal development, EMILIN-3 showed a peculiar and dynamic pattern of gene expression and protein distribution. EMILIN-3 mRNA was first detected at E8.5-E9.5 in the tail bud and in the primitive gut, and at later stages it became abundant in the developing gonads and osteogenic mesenchyme. Interestingly and in contrast to other EMILIN/Multimerin genes, EMILIN-3 was not found in the cardiovascular system. Despite the absence of the globular C1q domain, immunoprecipitation and Western blot analyses demonstrated that EMILIN-3 forms disulfide-bonded homotrimers and higher order oligomers. Circular dichroism spectroscopy indicated that the most C-terminal part of EMILIN-3 has a substantial α-helical content and forms coiled coil structures involved in EMILIN-3 homo-oligomerization. Transfection experiments with recombinant constructs showed that the EMI domain contributes to the higher order self-assembly but was dispensable for homotrimer formation. EMILIN-3 was found to bind heparin with high affinity, a property mediated by the EMI domain, thus revealing a new function for this domain that may contribute to the interaction of EMILIN-3 with other extracellular matrix and/or cell surface molecules. Finally, in vitro experiments showed that EMILIN-3 is able to function as an extracellular regulator of the activity of TGF-β ligands.
authors.affiliation: Department of Biomedical Sciences, University of Padova, I-35121 Padova, Italy.
authors.forename: Alvise
authors.initials: A
authors.lastname: Schiavinato
authors.forename: Ann-Kathrin A
authors.initials: AK
authors.lastname: Becker
authors.forename: Miriam
authors.initials: M
authors.lastname: Zanetti
authors.forename: Diana
authors.initials: D
authors.lastname: Corallo
authors.forename: Martina
authors.initials: M
authors.lastname: Milanetto
authors.forename: Dario
authors.initials: D
authors.lastname: Bizzotto
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bressan
authors.forename: Marija
authors.initials: M
authors.lastname: Guljelmovic
authors.forename: Mats
authors.initials: M
authors.lastname: Paulsson
authors.forename: Raimund
authors.initials: R
authors.lastname: Wagener
authors.forename: Paola
authors.initials: P
authors.lastname: Braghetta
authors.forename: Paolo
authors.initials: P
authors.lastname: Bonaldo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004220:Disulfides / Q000737:chemistry; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006493:Heparin / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011134:Polysaccharides / Q000378:metabolism; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors*
chemical_list: D000954:Antigens, Surface; D004220:Disulfides; C575003:EMILIN-3 protein, mouse; C089826:EMILIN3 protein, human; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011134:Polysaccharides; D016212:Transforming Growth Factor beta; D006493:Heparin