Scavenger receptor class B, type I (SR-BI) homo-dimerizes via its C-terminal region: fluorescence resonance energy transfer analysis. Biochim Biophys Acta 2007 Jul;1771(7):818-29
Date
06/09/2007Pubmed ID
17556017Pubmed Central ID
PMC1993887DOI
10.1016/j.bbalip.2007.04.019Scopus ID
2-s2.0-34250214535 (requires institutional sign-in at Scopus site) 37 CitationsAbstract
Expression of the scavenger receptor class B, type I (SR-BI) receptor facilitates high density lipoprotein cholesterol transport and correlates with protection against atherosclerosis. Studies have shown that SR-BI self-associates, but many of the techniques used to characterize SR-BI homo-oligomerization were wrought with the prospect of producing artifacts. Therefore, we employed fluorescence resonance energy transfer (FRET) to visualize SR-BI homo-oligomerization with the benefit of gaining information about its quaternary structure in the absence of typical membrane receptor artifacts. To this end, SR-BI was tagged at the N- or C-termini with either cyan (CFP) or yellow (YFP) fluorescent protein. To test whether SR-BI subunits oligomerize through N-N, N-C or C-C terminal interactions, we co-expressed the appropriate SR-BI fusion protein combinations in COS-7 cells and measured live-cell FRET following acceptor photobleaching. We did not observe FRET with co-transfection of SR-BI with CFP and YFP at the N-termini nor at the N- and C-termini, suggesting that the N-termini are not proximal to each other or to the C-termini. However, FRET was observed with co-transfection of SR-BI with CFP and YFP at the C-termini, suggesting that the C-terminal ends are within 10 nm of each other, consistent with SR-BI dimerization via its C-terminal region.
Author List
Sahoo D, Peng Y, Smith JR, Darlington YF, Connelly MAAuthor
Daisy Sahoo PhD Dean, Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCOS Cells
Dimerization
Fluorescence Resonance Energy Transfer
Humans
Luminescent Proteins
Photobleaching
Protein Transport
Recombinant Fusion Proteins
Scavenger Receptors, Class B
