alpha-Adrenergic-mediated activation of human reconstituted fibrinogen receptor (integrin alphaIIbbeta3) in Chinese hamster ovary cells.
This work reports the functional studies of CHO cells coexpressing alpha-adrenergic (alphaAR) and human fibrinogen (Fg) receptors (integrin alphaIIbbeta3). Stimulation of these cells with alpha-agonists produced a transient rise in the free cytosolic calcium (Ca(++)) accompanied by enhanced binding to soluble Fg, and these effects were prevented by specific alphaAR antagonists. The alpha-adrenergic-induced activation of alphaIIbbeta3 in CHO-alphaIIbbeta3-alphaAR increased the rate of adhesion and extension of cells onto Fg coated plates, and also induced a soluble Fg- and alphaIIbbeta3-dependent formation of cell aggregates, whereas no effects were observed by the stimulation of CHO-alphaIIbbeta3 cells. alpha-Adrenergic antagonists, the ligand mimetic peptide RGDS, pertussis toxin (PTX), or EDTA, they all prevented the alpha-adrenergic stimulation of adhesion and aggregation. However, inhibition of PKC prevented the alpha-adrenergic stimulation of cell adherence, whereas blocking the intracellular Ca(++) mobilization impeded the stimulation of cell aggregation. The alpha-adrenergic activation was associated with phosphorylation of a protein of approximately 100 kDa and proteins of the MAPK family. The former was selectively phosphorylated by alpha-adrenergic stimulation whereas the latter were phosphorylated by the binding of cells to Fg and markedly intensified by alpha-adrenergic stimulation.
Butta
Nora
N
Department of Physiopathology and Human Molecular Genetics, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu, 9, 28040-Madrid, Spain.
Larrucea
Susana
S
Gonzalez-Manchon
Consuelo
C
Alonso
Sonia
S
Parrilla
Roberto
R
D000199:Actins / Q000737:chemistry; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D006224:Cricetinae; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000494:pharmacology; D005340:Fibrinogen / Q000737:chemistry; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D008024:Ligands; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D037342:Pertussis Toxin / Q000494:pharmacology; D010766:Phosphorylation; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*
D000199:Actins; D000911:Antibodies, Monoclonal; D016895:Culture Media, Serum-Free; D008024:Ligands; D009842:Oligopeptides; D010455:Peptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011942:Receptors, Adrenergic, alpha; D005340:Fibrinogen; D004492:Edetic Acid; C046617:arginyl-glycyl-aspartyl-serine; D037342:Pertussis Toxin; D011493:Protein Kinase C; D002118:Calcium