A novel cell adhesion region in tropoelastin that mediates attachment to integrin alphaVbeta5 [Glycobiology and Extracellular Matrices]

November 29th, 2013 by Lee, P., Bax, D. V., Bilek, M. M. M., Weiss, A. S.

Tropoelastin protein monomers assemble to form elastin. Cellular integrin αVβ3 binds RKRK at the carboxy-terminal tail of tropoelastin. We probed cell interactions with tropoelastin by deleting the RKRK sequence in order to identify other cell binding interactions within tropoelastin. We found a novel human dermal fibroblast attachment and spreading site on tropoelastin that is located centrally in the molecule. Inhibition studies demonstrated that this cell adhesion was not mediated by either elastin binding protein or glycosaminoglycans. Cell interactions were divalent cation-dependent, indicating integrin dependence. Function blocking monoclonal antibodies revealed that αV-integrin(s) and integrin αVβ5 specifically were critical for cell adhesion to this part of tropoelastin. These data reveal a common αV integrin binding theme for tropoelastin: αVβ3 at the C-terminus and αVβ5 at the central region of tropoelastin. Each αV region contributes to fibroblast attachment and spreading but they differ in their effects on cytoskeletal assembly.