Chromatin condensation and nuclear fragmentation (CCNF) are hallmarks of apoptosis. CCNF is triggered by the activation of members of the caspase family, caspase-activated DNase (CAD/DFF40) and several novel proteins including AIF and CIDE. A new inducer of chromatin condensation was recently identified and designated Acinus (Apoptotic Chromatin Condensation Inducer in the Nucleus). The 220 kDa Acinus protein is cleaved by caspase-3 and an additional unknown protease to generate a 17 kDa peptide that which causes chromatin condensation in vitro when added to purified nuclei. Acinus also induces apoptotic chromatin condensation in cells. Three different spliced forms of Acinus have been identified in human and mouse and designated AcinusL, AcinusS, and AcinusS'. Acinus is ubiquitously expressed.Synonyms: Apoptotic chromatin condensation inducer in the nucleus, KIAA0670