Principles of Cellular Physiology 4: Nuclear Hormone Receptor Signalling Pathways

These flashcards cover key vocabulary and definitions related to nuclear hormone receptor signaling pathways and cellular physiology.

Nuclear Hormone Receptors

Intracellular receptors that act as transcription factors to regulate gene expression.

Ligand-gated Ion Channels

Receptors that open or close in response to the binding of a ligand.

G-protein Coupled Receptors (GPCRs)

Cell surface receptors that activate intracellular signaling pathways through the activation of G proteins.

Enzyme-linked Receptors

Receptors that act as enzymes or are directly linked to enzymes, initiating action upon ligand binding.

Hydrophilic Hormones

Water-soluble hormones that bind to cell membrane receptors and activate second messenger systems.

Lipophilic Hormones

Lipid-soluble hormones that cross cell membranes and bind to intracellular receptors.

Transcription Factors

Proteins that regulate the transcription of specific genes by binding to nearby DNA.

Second Messenger

A molecule that relays signals received at receptors on the cell surface to target molecules inside the cell.

GR (Glucocorticoid Receptor)

An intracellular receptor that binds glucocorticoids and regulates glucose metabolism.

MR (Mineralocorticoid Receptor)

An intracellular receptor that regulates sodium and water balance.

ER (Estrogen Receptor)

A nuclear receptor that regulates various biological processes in response to estrogen.

PR (Progesterone Receptor)

A nuclear receptor that mediates the effects of progesterone.

TR (Thyroid Hormone Receptor)

A nuclear receptor that regulates metabolism and development in response to thyroid hormones.

Retinoic Acid Receptor (RAR)

A nuclear receptor that regulates genes involved in development and differentiation.

Signal Transduction Pathways

A series of molecular events and chemical reactions that lead to a cellular response after receptor activation.

Gene Transcription

The process by which a specific segment of DNA is copied into RNA by RNA polymerase.

Hormone Response Element

Specific DNA sequences that hormone-receptor complexes bind to initiate transcription.

Steroid Hormones

Hormones derived from cholesterol that can easily cross cell membranes to bind intracellular receptors.

Serum-Glucocorticoid-Inducible Kinase 1 (SGK1)

A protein kinase that promotes sodium retention by affecting ENaC after being induced by aldosterone.

Epithelial Sodium Channel (ENaC)

A channel in the kidney that aids in sodium reabsorption; regulated by aldosterone and Nedd4-2.

Nedd4-2

A protein that promotes the internalization of ENaC, reducing sodium reabsorption.

Transactivation Domain

Part of nuclear receptors that activates transcription upon ligand binding.

Cytoplasmic Localization

The presence of receptors in the cytoplasm where they initially bind ligands.

Nuclear Localization Domain

A region in nuclear receptors that allows them to enter the nucleus.

Regulatory Protein

A protein that can inhibit or enhance the activity of receptors, affecting gene transcription.

Transcriptional Activation

The process whereby gene expression is initiated and increased following the binding of a receptor complex to DNA.

Thyroid Hormone Mechanism

The action mechanism involving thyroid hormone binding to its receptor, influencing gene expression.

Membrane Receptors

Receptors located on the cell membrane that respond to hydrophilic signaling molecules.

Nuclear Receptor Complex

Formed by hormone binding to a receptor, leading to DNA binding and gene activation.

Aldosterone

A steroid hormone that regulates sodium retention in the kidneys.

Hydrophilic vs. Lipophilic

Classification based on solubility affecting how hormones interact with their receptors.

Signal Molecule

A substance that initiates a response in a target cell upon receptor binding.