Mono-ADP-ribosyltransferases in human monocytes: regulation by lipopolysaccharide

• Published in: Biochemical journal 2002-03, Vol.362 (Pt 3), p.717-723
• Main Authors: Grahnert, Andreas, Friedrich, Maik, Pfister, Martin, Haag, Friedrich, Koch-Nolte, Friedrich, Hauschildt, Sunna
• Format: Article
• Language: English
• Subjects: Adenosine Diphosphate Ribose - metabolism; ADP Ribose Transferases; Antibodies, Monoclonal; Cell Membrane - enzymology; DNA Primers; Gene Expression Regulation, Enzymologic - drug effects; Humans; Lipopolysaccharides - pharmacology; Membrane Proteins - metabolism; Monocytes - drug effects; Monocytes - enzymology; Poly(ADP-ribose) Polymerases - blood; Poly(ADP-ribose) Polymerases - genetics; Reverse Transcriptase Polymerase Chain Reaction; Serum Albumin, Bovine - pharmacology
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/0264-6021:3620717

ADP-ribosyltransferase activity was shown to be present on the surface of human monocytes. Incubating the cells in the presence of BSA leads to an increase in enzyme activity. The acceptor amino acid mainly responsible for the ADP-ribose bond was identified as a cysteine residue. An increase in ADP-ribosyltransferase activity was observed when cells were treated for 16 h with bacterial lipopolysaccharide (LPS). Possible candidates for catalysing the reaction are mono-ADP-ribosyltransferases (ARTs). When measuring expression of the mRNA of ART1, 3, 4 and 5, only ART3 mRNA was detected in unstimulated monocytes. Upon stimulation for 16 h with LPS, lipoteichoic acid or peptidoglycan, ART4 mRNA was found to be expressed. No ART4 signal appeared after a 4 h exposure of the cells to LPS. Cell-surface proteins were labelled when incubating monocytes with [(32)P]NAD(+). Their molecular masses were 29, 33, 43, 45, 60 and 82 kDa. In response to LPS an additional protein of 31 kDa was found to be labelled. The bound label was resistant to treatment with NH(2)OH but sensitive to HgCl(2), characteristic of a cysteine-linked ADP-ribosylation.