US EPA

857686 

Journal Article 

Intracellular anion fluorescence assay for sodium/iodide symporter substrates 

Di Bernardo, J; Iosco, C; Rhoden, KJ 

2011 

Yes 

Analytical Biochemistry
ISSN: 0003-2697
EISSN: 1096-0309 

415 

1 

32-38 

English 

21545783 

10.1016/j.ab.2011.04.017 

WOS:000291407900005 

http://://WOS:000291407900005
Exit
 

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)(-)≫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. 

Fluorescence microscopy; Biosensor; Intracellular concentration; Yellow fluorescent protein; Anions; Thiocyanate; Nitrate; Chlorate; Perchlorate; Perrhenate; Thyroid gland