Based on limited published evidence, CYSRT1 is a cysteine-rich epidermal protein component of the stratum corneum that contributes to antimicrobial host defenses. CYSRT1 interacts with late cornified envelope (LCE) proteins in the upper epidermis and colocalizes with them in differentiated keratinocytes 1. The protein exhibits antibacterial activity against Pseudomonas aeruginosa and is induced by skin barrier disruption 1. CYSRT1 is highly conserved among vertebrates and participates in establishing the skin barrier and epidermal antimicrobial defense through protein-protein interactions and putative direct antimicrobial mechanisms 1.