Small Proline Rich Like Protein 1B (SPRL1B)

SPRL1B is one of the at least 20 genes expressed during epidermal differentiation and located on chromosomal band 1q21. This gene is involved in epidermal differentiation, and it is expressed at high levels in normal and psoriatic skin, but not in cultured keratinocytes or in any other tested cell types or tissues. Skin-specific. Expression was readily detected in adult trunk skin, adult arm skin, fetal skin, penal skin, vulva, esophagus and tongue. Not expressed in the cervix, rectum, lung, colon, or placenta.

The deduced protein contains 110 amino acids. Northern blot analysis detected XP5 expression in normal and psoriatic skin, but not in other tissues and cell lines examined, including normal keratinocytes and dermal fibroblasts.