Intracellular anion fluorescence assay for sodium/iodide symporter substrates.
Anal Biochem
; 415(1): 32-8, 2011 Aug 01.
Article
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| MEDLINE
| ID: mdl-21545783
ABSTRACT
The sodium/iodide symporter (NIS) is primarily responsible for iodide accumulation in the thyroid gland for the synthesis of thyroid hormones; however, it can also transport other lyotropic anions in the thyroid gland and nonthyroid tissues. Some NIS substrates have important physiological or clinical roles, and others are environmental contaminants with health-related consequences. The aim of this study was to assess the utility of a yellow fluorescent protein variant, YFP-H148Q/I152L, as a biosensor to monitor the cellular uptake of NIS substrates, including thiocyanate (SCN(-)), nitrate (NO(3)(-)), chlorate (ClO(3)(-)), perchlorate (ClO(4)(-)), and perrhenate (ReO(4)(-)). The fluorescence of purified YFP-H148Q/I152L was suppressed by anions with an order of potency of ReO(4)(-)>ClO(4)(-)=I(-)=SCN(-)=ClO(3)(-)>NO(3)(-)â«Cl(-). Anions also suppressed the fluorescence of YFP-H148Q/I152L expressed in FRTL-5, a thyroid cell line with high NIS expression. Quantitation of intracellular concentrations revealed differences among anions in the affinity and maximal velocity of NIS-mediated uptake as well as in the rate constant for passive efflux. These results suggest that YFP-H148Q/I152L can serve as an intracellular biosensor of NIS-transported anions and may be useful to study the physiology of endogenous anions as well as the health-related consequences of environmental anions.
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Animals
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En
Revista:
Anal Biochem
Año:
2011
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Article
País de afiliación:
Italia