SERPINB5
SERPINB5 (serpin family B member 5), also known as maspin or PI5, is a member of the ov-serpin subfamily that acts as a tumour suppressor. Unlike most serpins, it does not function as a serine protease inhibitor. Browse Assay Genie's current range of SERPINB5 research reagents below, or read on for the biology behind the target.
SERPINB5 is a tumour suppressor that blocks the growth, invasion and metastatic properties of mammary tumours. Although it belongs to the serpin family, it does not undergo the S (stressed) to R (relaxed) conformational transition characteristic of active serpins, and so it exhibits no serine protease inhibitory activity. Its tumour-suppressive role is therefore thought to rest on mechanisms distinct from classical protease inhibition.
The SERPINB5 gene encodes the protein Serpin B5, which UniProt places in the ov-serpin subfamily and which HGNC classifies within the serpin peptidase inhibitors gene group. UniProt annotates the protein as secreted into the extracellular space, while the NCBI Gene summary reports it as located in the cytoplasm. NCBI also notes a predicted serine-type endopeptidase inhibitor activity, which contrasts with the experimental annotation above. Mouse and rat both have a Serpinb5 ortholog.
NCBI Gene summarises SERPINB5 as acting upstream of or within extracellular matrix organisation, prostate gland morphogenesis and regulation of epithelial cell proliferation, and describes it as a biomarker of hepatocellular carcinoma. The protein is widely known as maspin, and earlier HGNC names describe it as serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 5. Researchers studying SERPINB5 often examine it alongside other clade B serpins to compare non-inhibitory and inhibitory family members.
SERPINB5 blocks the growth, invasion and metastatic properties of mammary tumours, making it a focus for studies of tumour suppression.
NCBI Gene describes SERPINB5 as a biomarker of hepatocellular carcinoma, supporting its use in liver cancer studies.
SERPINB5 is predicted to act in regulation of epithelial cell proliferation, relevant to studies of epithelial growth control.
Lacking the S to R transition and protease inhibitory activity, SERPINB5 is a useful comparator for studying how serpins diverge in function.
SERPINB5 acts as a tumour suppressor. It blocks the growth, invasion and metastatic properties of mammary tumours. NCBI Gene also links it to extracellular matrix organisation, prostate gland morphogenesis and regulation of epithelial cell proliferation, although some of these roles are predicted.
Yes, maspin and PI5 are alternative names for SERPINB5. Despite belonging to the serpin family, it does not undergo the S to R conformational transition of active serpins, so UniProt reports that it exhibits no serine protease inhibitory activity.
Mouse and rat each have a Serpinb5 ortholog, so the gene is conserved in common rodent models. Researchers should check the datasheet of any product for its validated reactivity before choosing a reagent for a given species.
Other clade B serpins and ov-serpin family members with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P36952; product specifications from Assay Genie datasheets.