Increased PARP-1levels in nuclear matrix isolated from heat shock treated rat liver

Author: Margarita Karapetian
Keywords: PARP-1, nuclear matrix, heat shock
Annotation:

Poly(ADP-ribose) polymerase-1 (PARP-1), a chromatin_associated enzyme that catalyzes the NAD+ - dependent addition of ADP_ribose polymers onto a variety of nuclear proteins, has been shown to be associated with the nuclear matrix. PARP-1 levels in the nuclear matrix vary depending on the matrix isolation method used. The nuclear matrix appears to be the most thermosensitive nuclear structure during heat shock. Here we provide evidence for the extensive translocation of PARP-1 from chromatin to the nuclear matrix during heat shock. This translocation is accompanied by inhibition of PARP activity in the nucleus and elevation of PARP activity in the nuclear matrix. Our data suggest that thermal destabilization of the nuclear matrix is less likely to contribute to the translocation of PARP-1 to the nuclear matrix.¬¬¬¬¬¬¬¬¬ However, it remains unclear whether this process is a specific response of eukaryotic cells to heat shock or whether it is the result of nonspecific protein aggregation. Regardless, the changes in PARP-1 subnuclear distribution as well as the inhibition of nuclear PARP activity during heat treatment are thought to be involved in the process of normal and/or tumor cell killing by hyperthermia.