Fluorescent labelling of membrane fatty acid transporter CD36 (SR-B2) in the extracellular loop.
PLoS One 2019;
14:e0210704. [PMID:
30673728 PMCID:
PMC6343965 DOI:
10.1371/journal.pone.0210704]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 01/01/2019] [Indexed: 11/19/2022] Open
Abstract
Context
Upon palmitate oversupply, membrane fatty acid-transporter CD36 (SR-B2) permanently translocates from endosomal storage to the sarcolemma, inducing lipotoxicity. CD36 translocation results from endosomal alkalinisation elicited by palmitate-induced disattachment of the cytoplasmic V1-subcomplex from the membrane-integrated V0-subcomplex of vacuolar-type H+-ATPase.
Objective
Develop a CD36 fluorescent labeling technique as initial step towards live cell imaging.
Methods
Three human CD36 (hCD36) mutants were constructed via insertion of a tetracysteine motif at different positions within the extracellular domain. Constructs were lentivirally transduced for subsequent CD36 labeling with fluorescein-arsenical hairpin-binder (FlAsH). Cell imaging was combined with V0/V1 immunostaining and Western blotting.
Results
Transduction of hCD36-wildtype and mutants yielded corresponding proteins in HL-1 cardiomyocytes. Tetracysteine mutant-2 (hCD36-TC2) showed similar fatty acid uptake to wildtype. FlAsH staining revealed a speckled pattern reminiscent of endosomes. We found decreased V1 co-localization with CD36 upon high-palmitate culturing. Conversely, V0 consistently co-localized with CD36.
Conclusion
hCD36-TC2 is a possible candidate for application of biarsenical dyes in live imaging studies pending further investigation. Our data is compatible with V0/V1 disassembly in high-palmitate-treated cells.
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