title: The interaction of angiocidin with tissue transglutaminase.
abstract: Angiocidin, a matrix bound and tumor associated protein, has been shown to inhibit tumor progression and angiogenesis. We previously demonstrated that angiocidin binds to thrombospondin-1 and alpha2beta1 integrin. We now show that angiocidin binds and is a preferred substrate for tissue transglutaminase-2 (tTgase). Angiocidin bound tTgase saturably with a Kd of 26 nM, while an angiocidin deletion mutant missing the matrix binding domain of angiocidin failed to bind tTgase. tTgase colocalized with angiocidin on endothelial cells. tTgase bound anti-angiocidin immunoprecipitates of endothelial cell lysates. Breast cancer cells expressing high levels of tTgase attached to angiocidin immobilized on tissue culture plates. Angiocidin was a preferred substrate for tTgase forming high molecular weight cross-linked multimers when treated with tTgase. Cross-linked angiocidin contained iso-peptide bonds as demonstrated by Western blotting and immunohistochemical colocalization studies using endothelial cells treated with angiocidin. Cross-linked angiocidin inhibited cell migration in contrast to monomeric angiocidin and inhibited localization of fibronectin (FN), a pro-tumorigenic matrix protein, into the extracellular matrix (ECM) of tumor and HUVE cells. Our studies provide an additional explanation for the anti-tumor activity of angiocidin suggesting that cross-linked angiocidin disrupts the tumor ECM making it less permissive for tumor growth.
authors.affiliation: Temple University, Department of Neuroscience, Center for Neurovirology, MERB-7th Floor, 3500 N. Broad Street, Philadelphia, PA 19140, USA.
authors.forename: Darryl Z
authors.initials: DZ
authors.lastname: L'Heureux
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Rothman
authors.forename: George P
authors.initials: GP
authors.lastname: Tuszynski
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D002648:Child; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D006168:Guinea Pigs; D006801:Humans; D009389:Neovascularization, Pathologic / Q000503:physiopathology; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D005353:Fibronectins; C498506:PSMD4 protein, human; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C000717608:TGM2 protein, human; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D046988:Proteasome Endopeptidase Complex; D019204:GTP-Binding Proteins