Serpin family B member 5 (SERPINB5)

Serpin family B member 5 (SERPINB5), also known as maspin, is a non-inhibitory member of the serpin superfamily of serine protease inhibitors, primarily encoded in humans by the SERPINB5 gene[1][3]. Originally identified as a tumor suppressor that inhibits cell invasion, migration, and metastasis, particularly in epithelial cells, its precise physiological function remains unclear due to conflicting findings from animal models and mechanistic studies[1][3][5]. Unlike classical serpins, maspin is mainly found intracellularly with nucleocytoplasmic distribution and is not secreted nor present at the cell surface[3]. It is proposed to modulate cell-matrix interactions, regulate cell adhesion and apoptosis, and affect chromatin state or gene expression, but it lacks direct protease inhibitory activity[1][3][5]. Maspin expression is regulated by tumor suppressors such as p53 and is subject to complex epigenetic control. Although frequently investigated as a tumor (especially breast and prostate cancer) prognostic marker or potential therapeutic target, there are no drugs currently approved that target SERPINB5 directly[1][5].

Other names

Serpin B5maspinPI-5peptidase inhibitor 5protease inhibitor 5 (maspin)serine (or cysteine) proteinase inhibitor clade B member 5serpin peptidase inhibitor clade B member 5

Not directly targeted by drugs; proposed to act via modulation of gene expression, inhibition of cell motility and invasion, regulation of apoptosis, potential inhibition of histone deacetylase 1 (HDAC1)[1][3][5]