Thyroid Hormone, TSH, and TRH Receptors

Thyroid Hormone Receptors

Thyroid hormone receptors described in 1972

First of the receptors to be always nuclear

Cloned

PP Presentation

Forms of Receptor

b Forms

a forms

Rev-ErbAa (also called ear-1)

PP Presentation

Properties of Major TR Isoforms

Regulation of expression

Tissue Levels of TR mRNA and T3 Binding Capacity

Tissue Distribution

Ontogeny

Domain Structure

Domain Structure of the TR Molecule

A/B domain

C domain

C Domain (cont)

DNA Binding Domain

D domain

E-domain

E-domain (cont)

P-box of TR

P-Box of TR and Similar Receptors

Domain Structure of the TR Molecule

Recognition site

Recognition site (cont)

Homo- and heterodimerization

Heterodimers

Crystalography

PP Presentation

PP Presentation

Ligand Binding Domain

Transcriptional regulation

Initiation complex

PP Presentation

Co-activators -repressors (1995)

Co-repressors

Co-activators

Co-activators (cont)

Co-activators (cont)

Resistance to thyroid hormone

RTH (cont)

Possible Mechanisms for RTH

Summary of RTH Mutations

Ligand Binding Domain

TRb knock out

TRb knock out (cont)

TRa knock out

TRa knock out (cont)

TRa knock out

TRH Receptors

Binding sites (and mRNA) found not only in anterior pituitary

Distribution of TRHR binding sites and/or mRNA

Cloning of TRHR

Binding of TRH is through hydrogen bonds

TRH Receptor Structure

G protein coupled

Couples with phospholipase-C through GTP-binding protein

Desentization

Downregulation

TSH Receptors

TSH Receptors

PP Presentation

PP Presentation

Domains

Domains (cont)

Genomic structure

TSHR structure

TSHR Structure (cont)

Homologous desentization involves decreased coupling of TSH-R to Gs


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