title: Transmembrane CEACAM1 affects integrin-dependent signaling and regulates extracellular matrix protein-specific morphology and migration of endothelial cells.
abstract: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1/CD66a), expressed on leukocytes, epithelia, and endothelia mediates homophilic cell adhesion. It plays an important role in cell morphogenesis and, recently, soluble CEACAM1 isoforms have been implicated in angiogenesis. In the present study, we investigated the function of long transmembrane isoform of CEACAM1 (CEACAM1-L) in cultured rat brain endothelial cells. We observed that expression of CEACAM1-L promotes network formation on basement membrane Matrigel and increased cell motility after monolayer injury. During cell-matrix adhesion, CEACAM1-L translocated into the Triton X-100-insoluble cytoskeletal fraction and affected cell spreading and cell morphology on Matrigel and laminin-1 but not on fibronectin. On laminin-1, CEACAM1-L-expressing cells developed protrusions with lamellipodia, showed less stress fiber formation, reduced focal adhesion kinase (FAK) tyrosine phosphorylation, and decreased focal adhesion formation leading to high motility. CEACAM1-L-mediated morphologic alterations were sensitive to RhoA activation via lysophosphatidic acid (LPA) treatment and dependent on Rac1 activation. Furthermore, we demonstrate a matrix protein-dependent association of CEACAM1-L with talin, an important regulator of integrin function. Taken together, our results suggest that transmembrane CEACAM1-L expressed on endothelial cells is implicated in the activation phase of angiogenesis by affecting the cytoskeleton architecture and integrin-mediated signaling.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Charité-Universitätsmedizin Berlin, Berlin-Dahlem, Germany.
authors.forename: Mario M
authors.initials: MM
authors.lastname: Müller
authors.forename: Bernhard B
authors.initials: BB
authors.lastname: Singer
authors.forename: Esther
authors.initials: E
authors.lastname: Klaile
authors.forename: Björn
authors.initials: B
authors.lastname: Obrink
authors.forename: Lothar
authors.initials: L
authors.lastname: Lucka
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D000943:Antigens, Differentiation / Q000378:metabolism*; D001921:Brain / Q000166:cytology; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D003094:Collagen; D003599:Cytoskeleton / Q000378:metabolism; D004338:Drug Combinations; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions; D016023:Integrins / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011509:Proteoglycans; D051381:Rats; D015398:Signal Transduction; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D004338:Drug Combinations; D016326:Extracellular Matrix Proteins; D016023:Integrins; D007797:Laminin; D020033:Protein Isoforms; D011509:Proteoglycans; C121346:laminin 1; C059485:matrigel; D019000:Phosphotyrosine; D003094:Collagen; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496052:Ptk2 protein, rat; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins