Identification of DNA-binding proteins on human umbilical vein endothelial cell plasma membrane.
The binding of anti-DNA antibodies to the endothelial cell is mediated through DNA, which forms a bridge between the immunoglobulin and the plasma membrane. We have shown that 32P-labelled DNA bound to the plasma membrane of human umbilical vein endothelial cells (HUVEC) by a saturable process, which could be competitively inhibited by non-radiolabelled DNA. In addition, DNA-binding was enhanced in HUVEC that had been treated with IL-1 alpha or tumour necrosis factor-alpha (TNF-alpha). DNA-binding proteins of mol. wt 46,000, 92,000, and 84,000 were identified by the binding of 32P-labelled DNA to plasma membrane proteins separated on SDS-PAGE. DNA-binding proteins of mol. wt 46,000 and 84,000 were also present in the cytosol and nucleus. Murine anti-DNA MoAb410 bound to a single band, at mol. wt 46,000, of plasma membrane protein, in the presence of DNA. Our results showed that DNA-binding proteins are present in different cellular fractions of endothelial cells. DNA-binding proteins on the cell membrane could participate in the in situ formation of immune deposits; and their presence in the cell nucleus suggests a potential role in the modulation of cell function.
Chan
T M
TM
Renal Unit, UMDS, University of London, UK.
Frampton
G
G
Cameron
J S
JS
D000911:Antibodies, Monoclonal / Q000276:immunology; D002462:Cell Membrane / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D004730:Endothelium, Vascular / Q000737:chemistry*; D006801:Humans; D008970:Molecular Weight; D014471:Umbilical Veins / Q000737:chemistry
D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D004247:DNA