A. Paire et al., CHARACTERIZATION OF THE RAT-THYROID IODIDE TRANSPORTER USING ANTIPEPTIDE ANTIBODIES - RELATIONSHIP BETWEEN ITS EXPRESSION AND ACTIVITY, The Journal of biological chemistry, 272(29), 1997, pp. 18245-18249
Anti-peptide antibodies directed against the C-terminal portion (amino
acids 603-618) of the rat thyroid iodide transporter (rTIT) have been
produced to characterize the molecular forms of rTIT in the rat thyro
id and in the functional rat thyroid cell line, FRTL-5. rTIT is locate
d on the basolateral membrane of rat thyroid follicular cells and rand
omly distributed on the plasma membrane of FRTL-5 cells that do not ex
hibit cell polarity, The major rTIT component corresponds to an 80-90k
Da glycosylated protein, After treatment of cell membrane fractions wi
th N-glycosidase F or incubation of FRTL-5 cells with tunicamycin, rTI
T has an apparent molecular mass of about 55 kDa, FRTL-5 cells culture
d in the presence of TSH exhibit a high rTIT content and a high iodide
uptake activity (IUA), Upon either removal of TSH or addition of cycl
oheximide, IUA declines more rapidly than rTIT. The half-life of rTIT
was about 4 days, Re-exposure of 7-day TSH-deprived FRTL-5 cells to TS
H causes a rapid synthesis of the glycosylated rTIT but a delayed re-i
nduction of IUA, Tunicamycin totally prevents the TSH-dependent re-exp
ression and activity of rTIT, Our data bring basic information on the
location, structure, and turnover of rTIT and suggest that its activit
y is subjected to diverse control mechanisms including regulatory prot
eins.