title: Multiple-interactions among EMILIN1 and EMILIN2 N- and C-terminal domains.
abstract: EMILIN1 and EMILIN2 belong to a family of extracellular matrix glycoproteins characterized by the N-terminal cysteine-rich EMI domain, a long segment with high probabilty for coiled-coil structure formation and a C-terminal gC1q domain. To study EMILIN1 and EMILIN2 interaction and assembly we have applied qualitative and quantitative two hybrid systems using constructs corresponding to the gC1q and EMI domains. The identified interactions were further confirmed in yeast extracts of co-transfected cells followed by co-immunoprecipitation. The data indicated that gC1q domains are able to self-interact as well as to interact one each other and with the EMI domains, but no self interactions were detected between the EMI domains. Furthermore EMILINs interactions were studied in 293-EBNA cells co-transfected with full lenght EMILIN1 and EMILIN2 constructs. Specific antibodies were able to co-immunoprecipitate EMILINs, indicating that also full-lenght proteins can give rise to non-covalent homo- and hetero-multimers even if reduced and alkylated before mixing. Immunofluorescence analysis on mouse cell cultures and tissues sections with specific antibodies showed co-distribution of EMILIN1 and EMILIN2. Thus, we can hypothesize that EMILINs multimers are formed by head-to-tail interaction between C-terminal and N-terminal domains of EMILIN1 and/or EMILIN2 but also by tail-to-tail interaction between gC1q domains. These multiple interactions may regulate homo-typic and/or hetero-typic linear and eventually lateral branching assemblies of EMILIN1 and EMILIN2 in tissues.
authors.affiliation: Experimental Oncology 2, CRO-IRCCS, National Cancer Institute, Aviano, PN, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Bot
authors.affiliation: Experimental Oncology 2, CRO-IRCCS, National Cancer Institute, Aviano, PN, Italy.
authors.forename: Eva
authors.initials: E
authors.lastname: Andreuzzi
authors.affiliation: Experimental Oncology 2, CRO-IRCCS, National Cancer Institute, Aviano, PN, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Capuano
authors.affiliation: Department of Molecular Medicine, University of Padova, Padova, Italy.
authors.forename: Alvise
authors.initials: A
authors.lastname: Schiavinato
authors.affiliation: Experimental Oncology 2, CRO-IRCCS, National Cancer Institute, Aviano, PN, Italy; MATI (Microgravity, Ageing, Training, Immobility) Excellence Center, University of Udine, Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Colombatti
authors.affiliation: Experimental Oncology 2, CRO-IRCCS, National Cancer Institute, Aviano, PN, Italy. Electronic address: rdoliana@cro.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Doliana
mesh_terms: D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: C426245:EMILIN2 protein, human; C486064:Emilin2 protein, mouse; D006023:Glycoproteins; D008562:Membrane Glycoproteins; C030340:elastin microfibril interface located protein
keywords: Domain interaction; Elastic fiber; Extracellular matrix; Multimer assembly