Signal Transduction and G Protein Coupled Receptors

These flashcards cover key concepts related to signal transduction, focusing on G Protein Coupled Receptors and related mechanisms.

Adrenaline

A hormone released by the adrenal glands during stress that prepares the body for fight or flight.

G Protein Coupled Receptors (GPCRs)

A large family of membrane receptors that interact with G proteins to transduce signals.

Signal Transduction

The process by which a cell responds to external signals, initiating a cascade of biochemical events.

Cyclic AMP (cAMP)

A secondary messenger molecule that activates protein kinase A (PKA) in response to signals from GPCRs.

Adenylyl Cyclase

An enzyme that converts ATP to cyclic AMP upon activation by G proteins.

Phosphorylation

The addition of a phosphate group to a molecule, often regulating the activity of proteins.

Primary Messenger

The first signaling molecule that binds to a receptor to initiate a signal transduction pathway.

Second Messenger

Molecules that relay signals from receptors on the cell surface to target molecules inside the cell.

G Protein

A molecular switch that transmits signals from a GPCR to downstream effectors, typically composed of three subunits: alpha, beta, and gamma.

Endocrine Signaling

Long-range signaling where hormones are released into the bloodstream to affect distant target cells.

Paracrine Signaling

Short-range signaling in which signals affect neighboring cells.

Juxtacrine Signaling

Signaling that occurs between two cells that are in direct contact.

Autocrine Signaling

Signaling where a cell secretes a signal that binds to its own receptors.

Signal Amplification

The process through which a single signal can lead to a large response in the cell, often through a cascade of reactions.

Receptor Desensitization

A decrease in receptor response to a ligand after prolonged exposure.

Guanine Nucleotide Exchange

The process of swapping GDP for GTP on G protein alpha subunit to activate it.

Receptor Tyrosine Kinases (RTKs)

A class of cell surface receptors that, when activated, can trigger multiple signaling cascades.

Calcium Ions (Ca2+)

An important secondary messenger involved in various signaling pathways and cellular responses.

Cholera Toxin

A bacterial toxin that activates Gs alpha, leading to excessive signaling through cyclic AMP and causing dehydration.

Phosphodiesterase

An enzyme that hydrolyzes cyclic AMP to AMP, effectively turning off signaling pathways that rely on cyclic AMP.

Agonist

A molecule that binds to a receptor and activates it to produce a biological response.

Antagonist

A molecule that binds to a receptor but does not activate it, effectively blocking the action of an agonist.