The PARP Family of Proteins

Name Localization ofaa kDa Dependence Modification Inhibition Branching 

Moreover, the DBD contains a bipartite nuclear localization s al (NLS) and a caspase-3 cleavage motif. The t ion between dhe DBD and the catalytic center contains a BRCT domain (BRCAl C-terminal domain) and an automodification domain. A hallmark of PARP-1 is that binding to DNA strand breaks results in a conformational change in the protein that leads to a 500 to 1,000 fold increase in catalytic activity. After activation by DNA strand breaks, PARP-1 covalently modifies nuclear taiget proteins such as histones and catalyzes automodification of other PARP-1 molecules. Because of its very high abundance in the cell 

Vaults are large ribonucleoprotein complexes found in eukaryotic cells. Isolated vault particles have a characteristic hollow barrel-like shape. They are predominandy localized in the cytoplasm and copurify with microtubules and ribosomes. An association with nuclear com- 

VPARP was shown to catalyze modification of MVP and automodification. The VPARP N-terminal region has a BRCT domain similar to that of PARP-1 and VPARP possesses a glutamic acid rich stretch that resembles the PARP-1 automodification domain, thereby indicating putatively similar functions. In addition, VPARP seems to have additional (unctions that are independent from vaults. This is suggested by the presence ofVPARP outside of typical vault locations such as cytoplasmic clusters ( VPARP-rods ) as well as its association with the nuclear matrix and the mitotic spindle.  

The function of the TCDD inducible PARP is not dear at present. A connection between TiPARP and memory formation has been implied, as the TiPARP geae has over 90% sequence homology to the rat RMl gene proposed to play a role in memory formation.  

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