Scavenger receptor class B member 1 (SRB1) also known as SR-BI is a protein that in humans is encoded by the SCARB1gene.[1] SR-BI functions as a receptor for high-density lipoprotein.[2]
SR-BI is crucial in lipid soluble vitamin uptake.[4]
In melanocytic cells SCARB1 gene expression may be regulated by the MITF.[5]
Species distribution
SR-BI has also been identified in the livers of non-mammalian species (turtle, goldfish, shark, chicken, frog, and skate), suggesting it emerged early in vertebrate evolutionary history. The turtle also seems to upregulate SB-RI during egg development, indicating that cholesterol efflux may be at peak levels during developmental stages.[6]
Clinical significance
SCARB1 along with CD81 is the receptor for the entry of the Hepatitis C virus into liver cells.[7]
Preclinical research
Although malignant tumors are known to display extreme heterogeneity, overexpression of SR-B1 is a relatively consistent marker in cancerous tissues. While SR-B1 normally mediates the transfer of cholesterol between high-density lipoproteins (HDL) and healthy cells, it also facilitates the selective uptake of cholesterol by malignant cells. In this way, upregulation of the SR-B1 receptor becomes an enabling factor for self-sufficient proliferation in cancerous tissue.[8][9]
SR-B1 mediated delivery has also been used in the transfection of cancer cells with siRNA, or small interfering RNAs. This therapy causes RNA interference, in which short segments of double stranded RNA acts to silence targeted oncogenes post-transcription. SR-B1 mediation reduces siRNA degradation and off-target accumulation while enhancing delivery to targeted tissues. In "metastatic and taxane-resistant models of ovarian cancer, rHDL-mediated siren delivery improved responses.[10]
Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.[§ 1]
↑Acton S, Rigotti A, Landschulz KT, Xu S, Hobbs HH, Krieger M (January 1996). "Identification of scavenger receptor SR-BI as a high density lipoprotein receptor". Science. 271 (5248): 518–20. doi:10.1126/science.271.5248.518. PMID8560269.
↑Rhainds D, Brissette L (January 2004). "The role of scavenger receptor class B type I (SR-BI) in lipid trafficking. defining the rules for lipid traders". The International Journal of Biochemistry & Cell Biology. 36 (1): 39–77. PMID14592533.
↑Valacchi G, Sticozzi C, Lim Y, Pecorelli A (July 2011). "Scavenger receptor class B type I: a multifunctional receptor". Annals of the New York Academy of Sciences. 1229: E1–7. doi:10.1111/j.1749-6632.2011.06205.x. PMID22239457.
↑Hoek KS, Schlegel NC, Eichhoff OM, Widmer DS, Praetorius C, Einarsson SO, Valgeirsdottir S, Bergsteinsdottir K, Schepsky A, Dummer R, Steingrimsson E (December 2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell & Melanoma Research. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID19067971.
↑Duggan AE, Marie RS, Callard IP (April 2002). "Expression of SR-BI (Scavenger Receptor Class B Type I) in turtle (Chrysemys picta) tissues and other nonmammalian vertebrates". The Journal of Experimental Zoology. 292 (5): 430–4. doi:10.1002/jez.10067. PMID11857477.
↑Mooberry LK, Sabnis NA, Panchoo M, Nagarajan B, Lacko AG (December 2016). "Targeting the SR-B1 Receptor as a Gateway for Cancer Therapy and Imaging". Frontiers in Pharmacology. 7 (466): 466. doi:10.3389/fphar.2016.00466. PMID28018216.
↑Rajora MA, Zheng G (2016). "Targeting SR-BI for Cancer Diagnostics, Imaging and Therapy". Frontiers in Pharmacology. 7 (Art. 326): 326. doi:10.3389/fphar.2016.00326. PMID27729859.
Further reading
Williams DL, Temel RE, Connelly MA (November 2000). "Roles of scavenger receptor BI and APO A-I in selective uptake of HDL cholesterol by adrenal cells". Endocrine Research. 26 (4): 639–51. doi:10.3109/07435800009048584. PMID11196441.
Krause BR, Auerbach BJ (March 2001). "Reverse cholesterol transport and future pharmacological approaches to the treatment of atherosclerosis". Current Opinion in Investigational Drugs. 2 (3): 375–81. PMID11575708.
Connelly MA, Williams DL (June 2004). "Scavenger receptor BI: a scavenger receptor with a mission to transport high density lipoprotein lipids". Current Opinion in Lipidology. 15 (3): 287–95. doi:10.1097/00041433-200406000-00008. PMID15166784.
Phillips RW (1978). "The new era in restorative dental materials". Operative Dentistry. 1 (1): 29–35. PMID1076467.
Skre H, Berg K (1974). "Cerebellar ataxia and total albinism: a kindred suggesting pleitotropism or linkage". Clinical Genetics. 5 (3): 196–204. doi:10.1111/j.1399-0004.1974.tb01682.x. PMID4838888.
Calvo D, Dopazo J, Vega MA (January 1995). "The CD36, CLA-1 (CD36L1), and LIMPII (CD36L2) gene family: cellular distribution, chromosomal location, and genetic evolution". Genomics. 25 (1): 100–6. doi:10.1016/0888-7543(95)80114-2. PMID7539776.
Calvo D, Vega MA (September 1993). "Identification, primary structure, and distribution of CLA-1, a novel member of the CD36/LIMPII gene family". The Journal of Biological Chemistry. 268 (25): 18929–35. PMID7689561.
Murao K, Terpstra V, Green SR, Kondratenko N, Steinberg D, Quehenberger O (July 1997). "Characterization of CLA-1, a human homologue of rodent scavenger receptor BI, as a receptor for high density lipoprotein and apoptotic thymocytes". The Journal of Biological Chemistry. 272 (28): 17551–7. doi:10.1074/jbc.272.28.17551. PMID9211901.
Li XA, Titlow WB, Jackson BA, Giltiay N, Nikolova-Karakashian M, Uittenbogaard A, Smart EJ (March 2002). "High density lipoprotein binding to scavenger receptor, Class B, type I activates endothelial nitric-oxide synthase in a ceramide-dependent manner". The Journal of Biological Chemistry. 277 (13): 11058–63. doi:10.1074/jbc.M110985200. PMID11792700.
Duncan KG, Bailey KR, Kane JP, Schwartz DM (April 2002). "Human retinal pigment epithelial cells express scavenger receptors BI and BII". Biochemical and Biophysical Research Communications. 292 (4): 1017–22. doi:10.1006/bbrc.2002.6756. PMID11944916.
Kawasaki Y, Nakagawa A, Nagaosa K, Shiratsuchi A, Nakanishi Y (July 2002). "Phosphatidylserine binding of class B scavenger receptor type I, a phagocytosis receptor of testicular sertoli cells". The Journal of Biological Chemistry. 277 (30): 27559–66. doi:10.1074/jbc.M202879200. PMID12016218.
Qi C, Chang J, Zhu Y, Yeldandi AV, Rao SM, Zhu YJ (August 2002). "Identification of protein arginine methyltransferase 2 as a coactivator for estrogen receptor alpha". The Journal of Biological Chemistry. 277 (32): 28624–30. doi:10.1074/jbc.M201053200. PMID12039952.
Johnson MS, Svensson PA, Borén J, Billig H, Carlsson LM, Carlsson B (June 2002). "Expression of scavenger receptor class B type I in gallbladder columnar epithelium". Journal of Gastroenterology and Hepatology. 17 (6): 713–20. doi:10.1046/j.1440-1746.2002.02776.x. PMID12100619.
Silver DL (September 2002). "A carboxyl-terminal PDZ-interacting domain of scavenger receptor B, type I is essential for cell surface expression in liver". The Journal of Biological Chemistry. 277 (37): 34042–7. doi:10.1074/jbc.M206584200. PMID12119305.
Bultel-Brienne S, Lestavel S, Pilon A, Laffont I, Tailleux A, Fruchart JC, Siest G, Clavey V (September 2002). "Lipid free apolipoprotein E binds to the class B Type I scavenger receptor I (SR-BI) and enhances cholesteryl ester uptake from lipoproteins". The Journal of Biological Chemistry. 277 (39): 36092–9. doi:10.1074/jbc.M201943200. PMID12138091.
