Membrane-bound transcription factor site-1 protease

Membrane-bound transcription factor site-1 protease (MBTPS1), also known as site-1 protease (S1P), is an enzyme that in humans is encoded by the MBTPS1 gene. This enzyme is a member of the subtilisin-like proprotein convertase family, which includes proteases that process protein and peptide precursors trafficking through regulated or constitutive branches of the secretory pathway.

Function

The MBTPS1 gene encodes an intramembrane zinc metalloprotease, which is essential in development and homeostasis. It functions in the endoplasmic reticulum-associated degradation (ERAD) pathway, where it cleaves the leucine zipper and sterol regulatory element-binding protein (SREBP) at site-1. This protease is also involved in other cellular processes, including lipid metabolism, cell growth, differentiation, and apoptosis.

Structure

The MBTPS1 protein is a type I transmembrane protein, meaning it has a single, alpha-helical transmembrane domain. The protein is synthesized as an inactive zymogen that is activated by autocatalytic cleavage.

Clinical significance

Mutations in the MBTPS1 gene have been associated with Ichthyosis follicularis, Alopecia, and Photophobia syndrome (IFAP syndrome), as well as with BRESHECK syndrome. These are rare genetic disorders characterized by skin abnormalities, hair loss, and sensitivity to light.

See also

• MBTPS2
• Sterol regulatory element-binding protein