Small proline-rich protein 2B (SPRR2B)

Small proline-rich protein 2B (SPRR2B) is a member of the small proline-rich protein family, originally identified as part of the cornified envelope in keratinocytes where it is cross-linked to contribute to the epidermal barrier. In addition to its structural functions in the skin, SPRR2B plays a non-canonical, regulatory role in other tissues. In cardiac fibroblasts during heart disease, SPRR2B functions as a regulatory subunit in the USP7/MDM2 ubiquitination complex, promoting the degradation of p53 and thereby facilitating cell cycle progression and fibroblast proliferation—mechanisms implicated in pathological cardiac fibrosis[1]. SPRR2B expression is also upregulated in several cancers, especially gastric adenocarcinoma, where it is associated with tumor growth, progression, and poor prognosis, acting through the MDM2-p53/p21 signaling pathway to enhance cancer cell proliferation[2]. There are currently no approved drugs directly targeting SPRR2B, and it is not considered a classic therapeutic target such as a receptor, enzyme, or transporter, but serves as a prognostic biomarker in some disease contexts[1][2].

Other names

Small proline-rich protein 2BSPRR2BSPR-2BSPRR2B protein