Essential for normal cell-cell adhesion in the cornified cell layers (PubMed:29758285). Important for proper integrity and mechanical strength of the stratum corneum of the epidermis (PubMed:29505760). In the stratum corneum of the epidermis, dispersed diffusely throughout the cytoplasm, while in the stratum granulosum, localized within keratohyalin granules (PubMed:19384417) (PubMed:21531719). In granular keratinocytes and in lower corneocytes, colocalizes with calpain-1/CAPN1. Expressed in skin, thymus, stomach and placenta, but not detected in heart, brain, liver, lung, bone marrow, small intestine, spleen, prostate, colon, adrenal gland, kidney, pancreas, mammary gland, bladder, thyroid, salivary gland and trachea. Weakly expressed in esophagus, tonsils and testis (at protein level). In the skin, strongly expressed in the upper stratum granulosum and lower stratum corneum, but not detected in the upper stratum corneum (at protein level) (PubMed:19384417) (PubMed:21531719). In scalp hair follicles, mainly restricted within the granular and cornified cells surrounding the infundibular outer root sheath, with weak expression in central and proximal outer root sheath (at protein level). Tends to be down-regulated in sporiatic lesions compared to non-lesional skin inthe same patients (PubMed:19384417). In cultured foreskin fibroblasts, up-regulated in response to Ca(2+) stimulation. Deiminated by PADI1, PADI2 or PADI3 in vitro. The deiminated form is degraded by calpain-1/CAPN1 more quickly and into shorter peptides than the intact protein. May be processed by calpain-1/CAPN1 in the uppermost epidermal layers. The disease is caused by variants affecting the gene represented in this entry. Belongs to the S100-fused protein family. In the N-terminal section; belongs to the S-100 family.