Proline-rich protein 4 (PRR4)

Proline-rich protein 4 (PRR4) is a member of the proline-rich protein family predominantly expressed in human lacrimal, submucosal, and salivary glands[1][2][3][4][5]. It lacks a conserved repetitive domain found in other proline-rich proteins[4]. PRR4 plays a role in protecting mucosal surfaces of the eye and oral cavity, likely by binding bacterial pathogens and plant tannins, and by inhibiting calcium phosphate precipitation. It is a major component of saliva and tears. Reduced expression of PRR4 has been observed in conditions such as dry eye syndrome, diabetic retinopathy, thyroid-associated orbitopathy, and several cancers including laryngeal and nasopharyngeal carcinoma, suggesting a role as a protective or suppressive molecule in epithelial inflammation and malignancy[1][2][3][4][5]. There is currently no evidence that PRR4 itself is a direct therapeutic target, receptor, enzyme, or a protein with characterized drug-binding or receptor-like properties.

Other names

Proline-rich protein 4PRR4PROL4LPRPLacrimal proline-rich proteinNasopharyngeal carcinoma-associated proline-rich protein 4proline-rich 4 (lacrimal)proline-rich polypeptide 4