The thyroid disruptor 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) prevents internalization of the TSH receptor
Author(s)
Picchietti, Simona
Belardinelli, Maria Cristina
Taddei, Anna Rita
Fausto, Anna Maria
Pellegrino, M.
Date Issued
2009
Type
Article
Abstract
The thyroid-stimulating hormone (TSH) receptor
(TSHr) was made specifically fluorescent by insertion of a
tetracysteine motif (TSHr-FlAsH) into the C-terminal end
and transiently transfected into COS-7 and HeLa cells. The
observation that TSH administration caused the intracellular
level of cAMP to increase in both TSHr-FlAsH-transfected
cell types indicated that the FlAsH binding motif did not
alter normal TSHr functioning. When transfected into HeLa
cells and stimulated with TSH, the TSHr-FlAsH receptor
exhibited a pronounced perinuclear labelling pattern,
whereas labelling remained on the cell surface following
pre-incubation with 1,1,1-trichloro-2,2-bis(p-chlorophenyl)
ethane (DDT). Chinese hamster ovary (CHO)-TSHr cells
probed with anti-TSHr antibodies were fluorescent mainly
in the proximity of the plasma membrane, with fluorescence
being primarily restricted to a juxta-nuclear position
when exposed to 10 mU/ml TSH for 1 or 5 min. However,
in the presence of DDT, the anti-TSHr fluorescence
maintained a peripheral location along the cell plasma
membrane, even if CHO-TSHr cells were stimulated with
TSH for 1 and 5 min. To verify that DDT acted specifically
on the TSHr, CHO cells transfected with the A2a receptor
were used as controls. Following a 1-min stimulation with
5’-(N-ethyl-carboxamido)-adenosine, A2a receptors were
gradually internalized regardless of the presence of DDT
in the culture medium. Finally, immunoelectron microscopy
of CHO-TSHr cells showed that a 1-min exposure to TSH
sufficed to displace anti-TSHr antibodies tagged with 10-
nm gold particles into coated pits and vesicles but that their
superficial location was retained along the plasma membrane
in the presence of DDT.
Additional information
L'articolo è disponibile sul sito dell'editore http://www.springerlink.com/
Citation
Cervia, D. et al. 2009. The thyroid disruptor 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) prevents internalization of the TSH receptor. "Cell and Tissue Research" 336(1): 31-40
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