Long-term alcohol effects on hepatic phosphoglucomutase activities in relation to posttranslational modification of the protein.
ADP-ribosylation is a posttranslational protein modification catalyzed by two classes of enzymes: mono-ADP-ribosyltransferase and poly-ADP-ribose polymerases. We previously demonstrated that long-term alcohol intake remarkably enhanced an endogenous ADP-ribosylation of a 58 kDa protein in rat liver and also identified the 58 kDa protein as phosphoglucomutase (PGM). To assess biological significance of this phenomenon, we tested the effects of long-term alcohol intake on PGM activities in connection with posttranslational modification of the protein. ADP-ribosylation of PGM was mono- rather than poly-ADP-ribosylation. Also, nonenzymatic binding of ADP-ribose was excluded. It was of note that ADP-ribosylation of exogenous PGM was remarkably increased by adding rat liver plasma membranes, and that the extent of the increase was greater in alcohol-fed rats than in pair-fed controls. Furthermore, PGM activities were significantly increased after long-term alcohol intake concomitant with increased ADP-ribosyltransferase activities toward PGM. In view of the variety of roles of PGM in the liver, such as carbohydrate metabolism and Ca2+ homeostasis, it is tempting to speculate that increased ADP-ribosylation of PGM may play a role in long-term alcohol effects on hepatocytes.
Nomura
F
F
Department of Clinical Pathology, Institute of Clinical Medicine, Tsukuba University, Ibaraki, Japan.
Miyake
M
M
Noda
M
M
Itoga
S
S
Nakai
T
T
D036002:ADP Ribose Transferases; D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008108:Liver Diseases, Alcoholic / Q000201:enzymology*; D008297:Male; D010733:Phosphoglucomutase / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000244:Adenosine Diphosphate; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases; D010733:Phosphoglucomutase