Proteolytic cleavage also results i

Proteolytic cleavage also results in inhibition of certain cellular activities.
Active caspases -3 and -7 can cleave poly(ADP-ribose) polymerase
(PARP)22,81,82 and DNA-PK,39,83-85 two enzymes that are thought to play a role
in DNA repair.86-88 The result of this cleavage is inactivation of these
enzymes37,89,90 and, presumably, inhibition of DNA repair. Likewise, cleavage
of the 70-kDa polypeptide of U1 small nuclear ribonucleoprotein particles91
and the C1 and C2 polypeptides of heterogeneous nuclear ribonucleoprotein
particles92 is thought to inhibit RNA splicing; and cleavage of DNA replication
factor C is thought to result in inhibition of DNA synthesis.93