TY - JOUR
T1 - Photoaffinity labelling of the rat liver nuclear thyroid hormone receptor with [125I]triiodothyronine
AU - David-Inouye, Yvonne
AU - Somack, Ralph
AU - Nordeen, Steven K.
AU - Apriletti, James W.
AU - Baxter, John D.
AU - Eberhardt, Norman L.
PY - 1982/11
Y1 - 1982/11
N2 - [125I]Triiodothyronine (T3) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that [125I]T3 covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 ± 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T3 and thyroxine (T4) similar to those that inhibit binding of [125I]T3 by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabeiled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that [125 I]T3 can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 ± 0.5 pH units.
AB - [125I]Triiodothyronine (T3) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that [125I]T3 covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 ± 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T3 and thyroxine (T4) similar to those that inhibit binding of [125I]T3 by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabeiled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that [125 I]T3 can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 ± 0.5 pH units.
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U2 - 10.1210/endo-111-5-1758
DO - 10.1210/endo-111-5-1758
M3 - Article
C2 - 6290199
AN - SCOPUS:0020216336
SN - 0013-7227
VL - 111
SP - 1758
EP - 1760
JO - Endocrinology
JF - Endocrinology
IS - 5
ER -