Figure 1.
Fig. 1. Posttranslational modification of proteins by
reversible ADP-ribosylation. ARTs and PARPs transfer the
ADP-ribose (ADPR) moiety from -NAD onto specific amino
acid side chains or onto ADPR moieties (X) of target proteins
under the release of nicotinamide. This modification may lead to
either activation or inactivation of the target protein.
Protein-ADP-ribosylhydrolases (ARHs and PARGs) hydrolyze the
-glycosidic bond
between ADPR and the side chain, thereby restoring normal
protein function. X can be Arg, Asp, Cys, diphthamide, Glu, or
ADPR. In the case of mono-ADP-ribosylation, R and R' are OH
groups. In the case of polyADP-ribosylation, attachment of ADPR
can take place at the R site (elongation) or at the R' site
(branching). In mammals, two distinct subfamilies of ARTs
(ART1–5, PARP1–17) and two distinct subfamilies of ARHs
(ARH1–3, PARG) exist.
-NAD onto specific amino
acid side chains or onto ADPR moieties (X) of target proteins
under the release of nicotinamide. This modification may lead to
either activation or inactivation of the target protein.
Protein-ADP-ribosylhydrolases (ARHs and PARGs) hydrolyze the
-glycosidic bond
between ADPR and the side chain, thereby restoring normal
protein function. X can be Arg, Asp, Cys, diphthamide, Glu, or
ADPR. In the case of mono-ADP-ribosylation, R and R' are OH
groups. In the case of polyADP-ribosylation, attachment of ADPR
can take place at the R site (elongation) or at the R' site
(branching). In mammals, two distinct subfamilies of ARTs
(ART1–5, PARP1–17) and two distinct subfamilies of ARHs
(ARH1–3, PARG) exist.