SignalStain^® Proliferation/Apoptosis IHC Sampler Kit #8109

Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) is a critical executioner of apoptosis, as it is either partially or totally responsible for the proteolytic cleavage of many key proteins such as the nuclear enzyme poly (ADP-ribose) polymerase (PARP) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments (2). Survivin is a 16 kDa anti-apoptotic protein highly expressed during fetal development and cancer cell malignancy (3). Survivin binds and inhibits caspase-3, controlling the checkpoint in the G2/M-phase of the cell cycle through inhibiting apoptosis and promoting cell division (4,5). Proliferating cell nuclear antigen (PCNA) is a member of the DNA sliding clamp family of proteins that assist in DNA replication (6). Multiple proteins involved in DNA replication, DNA repair, and cell cycle control bind to PCNA rather than directly associating with DNA, thus facilitating fast processing of DNA (reviewed in 7). PCNA protein expression is a well-accepted marker of proliferation, and PCNA (PC10) Mouse mAb has been used to assess PCNA levels in hundreds of scientific studies. Histone H3, H2A, H2B, and H4 make up the core histones of the nucleosome. In response to various stimuli, the amino-terminal tails of core histones undergo various post-translational modifications, including acetylation, phosphorylation, methylation and ubiquitination, which affect the accessibility of chromatin to transcription factors (8). Phosphorylation of Histone H3 at Ser10, Ser28 and Thr11 of histone H3 is tightly correlated with chromosome condensation during both mitosis and meiosis (9-11).