Ligand Concentration and Receptor Binding

Flashcards covering key concepts related to ligand concentration, receptor binding, and signal transduction pathways.

KD (Dissociation constant)

The concentration of ligand that occupies half of the receptors.

High KD

Indicates low affinity for the receptor.

Low KD

Indicates high affinity for the receptor.

Desensitization

The process where receptor sensitivity is decreased, often through phosphorylation.

Receptor-mediated endocytosis

A method for decreasing receptor sensitivity by pulling receptors into the cell.

Signal amplification

A process where one activated receptor can lead to multiple downstream signaling events.

Secondary messengers

Molecules, such as cAMP, that relays signals inside a cell after a receptor has been activated.

Beta-arrestin

A protein that plays a crucial role in receptor downregulation and desensitization.

G-Protein Coupled Receptors (GPCRs)

Receptors that activate intracellular signaling cascades via G-proteins upon ligand binding.

Adenylate Cyclase

An enzyme that converts ATP to cyclic AMP (cAMP), a crucial secondary messenger.

Cholera toxin

A toxin that prevents the hydrolysis of GTP on the G-protein, leading to prolonged activation of adenylate cyclase.

Ligand-Gated Ion Channels

Receptors that open in response to ligand binding, allowing specific ions to flow through.