Caspase-4 (ICErelII, TX, ICH-2) is a 43 kDa cytosolic protein with homology to the ICE/Ced-3 family of cysteine proteases. Functional similarity with ICE proteases include the ability of Caspase-4 to induce apoptosis when overexpressed. Caspase-4 exhibits protease activity, cleaving both itself and the p30 ICE/caspase-1 proenzyme. However, unlike ICE/caspase-1, caspase-4 displays no IL-1β processing activity. Caspase-4 mRNA is expressed in most adult human tissues, suggesting a broad tissue distribution.
The B25-1 antibody recognizes an ~43 kDa band corresponding to human Caspase-4 (TX). A recombinant human Caspase-4 protein fragment corresponding to amino acids 334-377 was used as immunogen.