Caspases are cysteine-aspartic proteases that post-translationally modify their substrates through cleavage at specific sites, which causes either substrate inactivation or a gain of function through the generation of active fragments. Currently, each caspase is categorized as either an initiator of apoptosis or an end-stage executioner. Caspase-6 was originally identified as an executioner cas...

Exposure to ionizing radiation (IR) during procedures such as abdominal and pelvic radiotherapy results in severe intestinal injury. In the current study, we demonstrated that a lethal dose of IR triggered epithelial cell apoptosis pyroptosis via Caspase-3 cleavage. The ginseng active ingredients, ginsenosides (GS) phenolic acids (GPA), significantly inhibited IR-induced IEC-6 cells. GS GPA als...

Homing endonucleases typically contain one of four conserved catalytic motifs, and other elements that confer tight DNA binding. I-CreII, which catalyzes homing of the Cr.psbA4 intron, is unusual in containing two potential catalytic motifs, H-N-H and GIY-YIG. Previously, we showed that cleavage by I-CreII leaves ends (2-nt 3' overhangs) that are characteristic of GIY-YIG endonucleases, yet it ...

Necrosis and apoptosis differentially contribute to myocardial injury. Determination of the contribution of these processes in ischemia-reperfusion injury would allow for the preservation of myocardial tissue. Necrosis and apoptosis were investigated in Langendorff-perfused rabbit hearts (n = 47) subjected to 0 (Control group), 5 (GI-5), 10 (GI-10), 15 (GI-15), 20 (GI-20), 25 (GI-25), and 30 mi...

Keratins 8 (K8) and 18 (K18) are major components of intermediate filaments (IFs) of simple epithelial cells and tumors derived from such cells. Structural cell changes during apoptosis are mediated by proteases of the caspase family. During apoptosis, K18 IFs reorganize into granular structures enriched for K18 phosphorylated on serine 53. K18, but not K8, generates a proteolytic fragment duri...

Caspases are proteases that initiate and execute apoptotic cell death. These caspase-dependent events are caused by cleavage of specific substrates that propagate the proapoptotic signal. A number of techniques have been developed to follow caspase activity in vitro and from apoptotic cellular extracts. Many of these techniques use molecules that are based on optimal peptide motifs for each cas...

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces programmed cell death through the caspase activation cascade and translocation of cleaved Bid (tBid) by the apical caspase-8 to mitochondria to induce oligomerization of multidomain Bax and Bak. However, the roles of prosurvival Bcl-2 family proteins in TRAIL apoptosis remain elusive. Here we showed that, besides the specif...

Caspase cleavage of huntingtin (htt) and nuclear htt accumulation represent early neuropathological changes in brains of patients with Huntington's disease (HD). However, the relationship between caspase cleavage of htt and caspase activation patterns in the pathogenesis of HD remains poorly understood. The lack of a phenotype in YAC mice expressing caspase-6-resistant (C6R) mutant htt (mhtt) h...

Different classes of anticancer drugs may trigger apoptosis by acting on different subcellular targets and by activating distinct signaling pathways. Here, we report that betulinic acid (BetA) is a prototype cytotoxic agent that triggers apoptosis by a direct effect on mitochondria. In isolated mitochondria, BetA directly induces loss of transmembrane potential independent of a benzyloxycarbony...