Membrane-bound transcription factor peptidase, site 1

• OMIM: 603 355
• UniProt: Q14703
• MGI: 1927235

MBTPS1 (synonyms: S1P, site-1 protease, and further in iHOP ) is membrane bound transcription factor protease, site 1

MBTPS1 is a protease which plays a role in cholesterol metabolism of the human and other eukaryotic cells. It belongs to the subtilisin family of serine proteases.

Function

This enzyme breaks in human cells the SREBPs ( sterol regulatory element binding protein), proteolytically and activates them thereby transcription factors that then in the nucleus increased the rate of transcription of several genes (such as have the genes of the HMG -CoA reductase, HMG CoA synthase, prenyltransferase and the LDL receptor in their promoter region of the SRE ( sterol regulatory element ), which can bind to the activated SREBPs ). This only happens when SREBP previously SCAP ( SREBP cleavage activating protein ) bound; this binding can be released when SCAP binds cholesterol. This provides a feedback mechanism which can be approximately described as follows: When there is little cholesterol is present in the cell, is increasing the transcription of several genes as described above which are necessary for the synthesis of cholesterol of the cell and for as long until the formed cholesterol to SCAP binds. There are many other feedback about the cholesterol inhibits its formation, the HMG- CoA reductase is eg also inhibited directly.