Non-apoptotic caspase involved in epidermal differentiation. Is the predominant caspase in epidermal stratum corneum (PubMed:15556625). Seems to play a role in keratinocyte differentiation and is required for cornification. Regulates maturation of the epidermis by proteolytically processing filaggrin (By similarity). In vitro has a preference for the substrate [WY]-X-X-D motif and is active on the synthetic caspase substrate WEHD-ACF (PubMed:16854378, PubMed:19960512). Involved in processing of prosaposin in the epidermis (By similarity). May be involved in retinal pigment epithelium cell barrier function (PubMed:25121097). Involved in DNA degradation in differentiated keratinocytes probably by cleaving DFFA/ICAD leading to liberation of DFFB/CAD (PubMed:24743736). Inhibited by caspase-1 inhibitor YVAD-FMK and the pan-caspase inhibitor VAD-FMK. Heterodimer of a large and a small subunit, both processed from the precursor; the mature active form is a p17/p10 dimer and the intermediate form a p20/p8 dimer. Expressed in keratinocytes of adult skin suprabasal layers (from spinous layers to the stratum granulosum and stratum corneum) (at protein level). Expressed in keratinocytes of hair shaft and sebaceous glands (at protein level). In psoriatic skin only expressed at very low levels (PubMed:11175259). The p17/10 mature form is expressed in epidermis stratum corneum, the p20/p8 intermediate form in epidermis upper granular cells of the stratum granulosum (PubMed:22825846). In undifferentiated keratinocytes under postconfluency growth conditions (in vitro) (PubMed:11175259). By high glucose in retinal pigment epithelia cells (PubMed:25121097). Maturation by proteolytic processing appears to be a two-step process. The precursor is processed by KLK7 to yield the p20/p8 intermediate form which acts on the precursor to yield the p17/p10 mature form (PubMed:22825846). Initially, cleavage between Ile-152 and Lys-153 has been proposed to yield the large and small subunits of the active enzyme (PubMed:12200134). The disease is caused by variants affecting the gene represented in this entry. Expressed in bacteria requires high concentrations of kosmotropic salts to be activated (PubMed:15301553). The mature and the intermediate form differ in activity towards synthetic caspase substrates: the p17/p10 mature form but not the p20/p8 intermediate form is active on WEHD-MCA; p20/p8 is active on a number of other caspase substrates without any marked preference (VEID-AFC, DEVD-AFC, LEVD-AFC and LEHD-AFC) (PubMed:22825846). Belongs to the peptidase C14A family.