Small proline-rich protein 5 (SPRR5)

Small proline-rich protein 5 (SPRR5) is a protein expressed in human epidermal keratinocytes and acts as an essential positive regulator of keratinocyte differentiation[1][6][3]. The SPRR5 gene is located within the epidermal differentiation complex (EDC) and is highly induced during late stages of epidermal differentiation, where it promotes the expression of other genes critical for terminal differentiation and skin barrier formation[1][8]. SPRR5 functions are distinct from other SPRR family members due to its unique evolutionary profile and regulation by transcription factors such as p63 and repression by long non-coding RNA LINC00941[1][2]. Reduced SPRR5 expression leads to significant defects in keratinocyte differentiation, demonstrating its necessity for proper epidermal homeostasis[1][3]. While SPRR5 shares similarity with other small proline-rich proteins thought to contribute structurally to the cornified envelope of the skin, evidence suggests that SPRR5 also has specific regulatory functions in gene expression programs related to epithelial biology[1][2][6]. There is emerging but inconclusive evidence for its involvement in the pathogenesis of epithelial cancers and skin disorders; however, it is not a recognized drug target, and no specific drugs, mechanisms of action, or biomarker roles have been established for SPRR5 to date[2][4][5][7].

Other names

SPRR5small proline-rich protein 5putative small proline-rich protein 5