title: Crosslinking and G-protein functions of transglutaminase 2 contribute differentially to fibroblast wound healing responses.
abstract: Tissue transglutaminase (TG2) affects cell-matrix interactions in cell spreading, migration and extracellular matrix (ECM) reorganisation. Using fibroblasts deficient in TG2 or overexpressing normal or crosslinking-deficient enzyme, we show that the extracellular crosslinking activity and intracellular G-protein function in signal transduction contribute differentially to regulation of cell-matrix interactions. TG2-deficient cells displayed normal attachment but delayed spreading on ECM substrata and defects in motility unrelated to crosslinking. Blocking antibodies to TG2 failed to induce similar defects in normal fibroblasts. TG2-deficient fibroblasts had defects in focal adhesion turnover and stress fibre formation, showed changes in focal adhesion kinase (FAK) phosphorylation and failed to activate protein kinase C alpha (PKCalpha). Phospholipase C (PLC) and PKCalpha inhibitors blocked spreading of normal fibroblasts whilst PKC activators induced spreading in TG2-deficient cells. In contrast, ECM remodelling was not only compromised by TG2 deficiency but also by overexpression of dominant negative enzyme and TG inhibitors. TG2 activity increased matrix tension and was required for membrane type 1-MMP (MT1-MMP)-dependent activation of MMP-2. Our results demonstrate that TG2 is involved in the control of dynamic adhesion formation in cell spreading and migration via regulation of phospholipase C activity. By virtue of its crosslinking activity, the enzyme plays a central role in regulating ECM remodelling.
authors.affiliation: Department of Oral Surgery, Medicine and Pathology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XY, UK.
authors.forename: Phil
authors.initials: P
authors.lastname: Stephens
authors.forename: Pascale
authors.initials: P
authors.lastname: Grenard
authors.forename: Pascale
authors.initials: P
authors.lastname: Aeschlimann
authors.forename: Martin
authors.initials: M
authors.lastname: Langley
authors.forename: Emma
authors.initials: E
authors.lastname: Blain
authors.forename: Rachael
authors.initials: R
authors.lastname: Errington
authors.forename: David
authors.initials: D
authors.lastname: Kipling
authors.forename: David
authors.initials: D
authors.lastname: Thomas
authors.forename: Daniel
authors.initials: D
authors.lastname: Aeschlimann
mesh_terms: D002448:Cell Adhesion; D002465:Cell Movement; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism; D016133:Polymerase Chain Reaction; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011493:Protein Kinase C / Q000378:metabolism; D051571:Protein Kinase C-alpha; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D011503:Transglutaminases / Q000737:chemistry / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism; D014945:Wound Healing
chemical_list: D003432:Cross-Linking Reagents; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D010738:Type C Phospholipases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D019204:GTP-Binding Proteins