title: Transglutaminase-mediated oligomerization of the fibrin(ogen) alphaC domains promotes integrin-dependent cell adhesion and signaling.
abstract: Interactions of endothelial cells with fibrin(ogen) are implicated in inflammation, angiogenesis, and wound healing. Cross-linking of the fibrinogen alphaC domains with factor XIIIa generates ordered alphaC oligomers mimicking polymeric arrangement of the alphaC domains in fibrin. These oligomers and those prepared with tissue transglutaminase were used to establish a mechanism of the alphaC domain-mediated interaction of fibrin with endothelial cells. Cell adhesion and chemical cross-linking experiments revealed that oligomerization of the alphaC domains by both transglutaminases significantly increases their RGD (arginyl-glycyl-aspartate)-dependent interaction with endothelial alphaVbeta3 and to a lesser extent with alphaVbeta5 and alpha5beta1 integrins. The oligomerization promotes integrin clustering, thereby increasing cell adhesion, spreading, formation of prominent peripheral focal contacts, and integrin-mediated activation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK) signaling pathways. The enhanced integrin clustering is likely caused by ordered juxtaposition of RGD-containing integrin-binding sites upon oligomerization of the alphaC domains and increased affinity of these domains for integrins. Our findings provide new insights into the mechanism of the alphaC domain-mediated interaction of endothelial cells with fibrin and imply its potential involvement in cell migration. They also suggest a new role for transglutaminases in regulation of integrin-mediated adhesion and signaling via covalent modification of integrin ligands.
authors.affiliation: University of Maryland School of Medicine, 15601 Crabbs Branch Way, Rockville, MD 20855, USA. belkina@usa.redcross.org
authors.forename: Alexey M
authors.initials: AM
authors.lastname: Belkin
authors.forename: Galina
authors.initials: G
authors.lastname: Tsurupa
authors.forename: Evgeny
authors.initials: E
authors.lastname: Zemskov
authors.forename: Yuri
authors.initials: Y
authors.lastname: Veklich
authors.forename: John W
authors.initials: JW
authors.lastname: Weisel
authors.forename: Leonid
authors.initials: L
authors.lastname: Medved
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002448:Cell Adhesion; D019281:Dimerization; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology*; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D006168:Guinea Pigs; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D008099:Liver; D009842:Oligopeptides / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D017434:Protein Structure, Tertiary; D019030:Receptors, Vitronectin / Q000378:metabolism; D015398:Signal Transduction; D011503:Transglutaminases / Q000378:metabolism* / Q000502:physiology; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D039302:Integrin alphaVbeta3; D016023:Integrins; D009842:Oligopeptides; D010446:Peptide Fragments; D019030:Receptors, Vitronectin; C098000:fibrinogen alphaC; C064660:integrin alphaVbeta5; C047981:arginyl-glycyl-aspartic acid; D005340:Fibrinogen; D011503:Transglutaminases