title: Functional characterization of integrin alpha6beta4 adhesion interactions using soluble integrin constructs reveals the involvement of different functional domains in the beta4 subunit.
abstract: Integrin alpha6beta4-mediated adhesion interactions play key roles in keratinocyte and epithelial tumor cell biology. In order to evaluate how alpha6beta4 adhesion interactions contribute to these important cellular processes, the authors generated soluble versions of the integrin by recombinant expression of the subunit ectodomains fused to a human immunoglobulin G (IgG) Fc constant domain. Coexpression of the appropriate subunits enabled dimerization, secretion and purification of stable Fc-containing alpha6beta4 heterodimers. The soluble proteins exhibited the same metal ion and ligand dependency in their binding characteristics as intact alpha6beta4. Using these reagents in combination with anti-beta4 antibodies, the authors identified two distinct functional epitopes on the beta4 subunit. They demonstrated the involvement of one epitope in adhesion interactions and the other in regulating adhesion-independent growth in alpha6beta4-expressing tumor cell lines. The availability of these soluble integrin reagents and the data provided herein help to further delineate the structure-function relationships regulating alpha6beta4 signaling biology.
authors.affiliation: Biogen Idec, San Diego, California, USA.
authors.forename: Ling Ling
authors.initials: LL
authors.lastname: Chen
authors.forename: Veronica
authors.initials: V
authors.lastname: Gabarra
authors.forename: Samuel
authors.initials: S
authors.lastname: Cho
authors.forename: Beth
authors.initials: B
authors.lastname: Browning
authors.forename: Xianjun
authors.initials: X
authors.lastname: Cao
authors.forename: Heather
authors.initials: H
authors.lastname: Huet
authors.forename: Anne
authors.initials: A
authors.lastname: Cheung
authors.forename: Ron
authors.initials: R
authors.lastname: Morena
authors.forename: Miriam
authors.initials: M
authors.lastname: Ramirez
authors.forename: Michael
authors.initials: M
authors.lastname: Shields
authors.forename: R
authors.initials: R
authors.lastname: Blake Pepinsky
authors.forename: Karen
authors.initials: K
authors.lastname: McLachlan
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D016466:CHO Cells; D002448:Cell Adhesion; D002450:Cell Communication; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D019281:Dimerization; D006801:Humans; D039161:Integrin alpha6beta4 / Q000502:physiology*; D039663:Integrin beta4 / Q000737:chemistry* / Q000276:immunology / Q000502:physiology; D020014:K562 Cells; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction; D013329:Structure-Activity Relationship
chemical_list: D000906:Antibodies; D039161:Integrin alpha6beta4; D039663:Integrin beta4; D011993:Recombinant Fusion Proteins