Protein Family Models

Sterol regulatory element-binding proteins (SREBPs) are membrane-bound transcription factors that promote lipid synthesis in animal cells. They are embedded in the membranes of the endoplasmic reticulum (ER) in a helical hairpin orientation and are released from the ER by a two-step proteolytic process. Proteolysis begins when the SREBPs are cleaved at Site-1, which is located at a leucine residue in the middle of the hydrophobic loop in the lumen of the ER [1]. Upon proteolytic processing SREBP can activate the expression of genes involved in cholesterol biosynthesis and uptake. SCAP stimulates cleavage of SREBPs via fusion of the their two C-termini [2]. This domain is the transmembrane region that traverses the membrane eight times and is the sterol-sensing domain of the cleavage protein [4]. WD40 domains are found towards the C-terminus. [1]. 9488713. Cleavage of sterol regulatory element-binding proteins (SREBPs) at site-1 requires interaction with SREBP cleavage-activating protein. Evidence from in vivo competition studies. Sakai J, Nohturfft A, Goldstein JL, Brown MS;. J Biol Chem. 1998;273:5785-5793. [2]. 17604677. Endoplasmic reticulum stress causes the activation of sterol regulatory element binding protein-2. Colgan SM, Tang D, Werstuck GH, Austin RC;. Int J Biochem Cell Biol. 2007;39:1843-1851. [3]. 9242699. Identification of complexes between the COOH-terminal domains of sterol regulatory element-binding proteins (SREBPs) and SREBP cleavage-activating protein. Sakai J, Nohturfft A, Cheng D, Ho YK, Brown MS, Goldstein JL;. J Biol Chem. 1997;272:20213-20221. [4]. 12482938. Three mutations in sterol-sensing doma. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16

Members of this family are putative integral membrane proteins from bacteria. Several of the members are mycobacterial proteins. Many of the proteins contain two copies of this aligned region. The function of these proteins is not known, although it has been suggested that they may be involved in lipid transport [1]. [1]. 10694977. Analysis of the proteome of Mycobacterium tuberculosis in silico. Tekaia F, Gordon SV, Garnier T, Brosch R, Barrell BG, Cole ST;. Tuber Lung Dis 1999;79:329-342. (from Pfam)

Date:

2024-10-16

efflux RND (resistance-nodulation-cell division) transporter permease subunit similar to the archaeal/bacterial protein export membrane protein SecD/SecF

Date:

2024-11-19