Nuclear Receptor Signaling
Nuclear Receptor Signaling - Related Videos
01:31
Transducer Mechanism: Nuclear Receptors
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2023
Nuclear receptors, or NRs, are unique transcription factors that regulate gene transcription and affect the cellular pathways involved in reproduction, development, or metabolism. Their ability to be stimulated by small lipophilic ligands and control vital cellular processes makes them ideal drug targets. Nearly 10-15% of currently prescribed drugs target these receptors. About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
01:46
Nuclear Localization Signals and Import
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2023
Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of 2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...
10:13
Measuring G-protein-coupled Receptor Signaling via Radio-labeled GTP Binding
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Cited by 11 •
2017
Guanosine triphosphate (GTP) binding is one of the earliest events in G-Protein-Coupled Receptor (GPCR) activation. This protocol describes how to pharmacologically characterize specific GPCR-ligand interactions by monitoring the binding of the radio-labeled GTP analog, [35S]guanosine-5'-O-(3-thio)triphosphate ([35S]GTPγS), in response to a ligand of interest.
01:41
Signal Sequences and Sorting Receptors
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2023
Signal sequences are short amino acid sequences that guide newly synthesized proteins to their proper location within the cell. Classical signal sequences are fifteen to sixty amino acids long and present at the N-terminus of a polypeptide chain. Each signal sequence has a conserved segment of basic residues towards their N terminus, a hydrophobic core, and a C-terminus rich in polar residues. The C-terminus also contains a signal cleavage site and features a -3 -1 sequence motif. The -3-1...
01:28
Insulin: The Receptor and Signaling Pathways
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2024
Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
FAQs
Ligand binding changes the receptor’s conformation, which determines whether it recruits coactivators or corepressors. These regulatory proteins influence the receptor’s activity after it binds specific DNA response elements. Coactivator recruitment can support increased transcription, whereas corepressor recruitment can support reduced transcription. This molecular switch helps connect hormone or ligand presence with changes in cellular gene expression.
Coactivators and corepressors help determine the direction and strength of transcriptional regulation. After ligand binding changes receptor conformation, the receptor can favor one type of regulatory partner over the other. This provides a mechanism for increasing or decreasing gene expression rather than producing a single uniform response. Their involvement helps explain how related signals can generate different cellular outcomes.
DNA response elements provide specific genomic sites through which activated receptors influence transcription. Binding at these sites connects receptor activation to regulation of particular genes, while recruited coactivators or corepressors help determine whether transcription rises or falls. Consequently, the response depends not only on ligand binding but also on which receptor-controlled genes contain relevant response elements.
A focused analysis follows the pathway from ligand binding through receptor conformational change, regulatory-partner recruitment, DNA response-element binding, and altered transcription. Examining these linked events helps researchers identify where regulation occurs and how a signal produces a biological effect. This framework is useful for interpreting receptor activity in development, metabolism, reproduction, and disease-related investigations.
The pathway provides several points for understanding how therapeutic ligands produce effects: receptor binding, conformational change, recruitment of coactivators or corepressors, DNA interaction, and transcriptional regulation. Connecting these molecular events with physiological outcomes can guide investigation of drug actions. This is particularly relevant for medicines related to corticosteroids, thyroid hormones, vitamin D, retinoids, and metabolic regulators.
Nuclear receptor signaling is relevant to endocrine disorders, cancer, inflammation, and metabolic disease, while also contributing to development, metabolism, and reproduction. Its medical importance comes from the way altered ligand-regulated gene expression can affect broad physiological functions. Studying the pathway therefore helps connect molecular regulation with disease mechanisms and with the effects of hormone-related therapies.