The role of the Fgr tyrosine kinase in the control of the adhesive properties of U937 monoblastoid cells and their derivatives.
In humans, expression of the cellular proto-oncogene c-fgr is normally restricted to mature cells of the myeloid lineage, mantle zone B cells and various myeloid and B-cell lines. Previous studies of the monoblastoid cell line, U937, showed that c-fgr expression increased following differentiation, but its role in monocytes and related cells has not been defined in functional terms. We therefore investigated the role of c-fgr in U937 cells transfected with the c-fgr gene such that its expression could be manipulated independent of differentiation. Induction of the transfected c-fgr gene by cadmium ions did not affect cell proliferation, responses to phorbol 12-myristate 13-acetate (PMA), dihydroxycholecalciferol (DHCC), tumour necrosis factor-alpha (TNF-alpha) or retinoic acid, or phagocytosis of antibody-coated sheep red blood cells. However, there was increased surface expression of CD54 (intracellular adhesion molecule-1; ICAM-1) and CD102 (ICAM-2) and decreased surface expression of CD50 (ICAM-3) compared with cells that had been transfected with plasmid only and treated in the same way. These findings suggest that the product of the c-fgr gene may be important in control of relative adhesive properties of mature monocytic cells.
Faulkner
L
L
Department of Immunology, University College London Medical School, UK.
Patel
M
M
Brickell
P M
PM
Katz
D R
DR
D015703:Antigens, CD / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002448:Cell Adhesion / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002455:Cell Division / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D009000:Monocytes / Q000276:immunology*; D010587:Phagocytosis; D011505:Protein-Tyrosine Kinases / Q000276:immunology; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
D015703:Antigens, CD; D015815:Cell Adhesion Molecules; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; C053102:proto-oncogene proteins c-fgr; D019061:src-Family Kinases