G-Protein Signaling Lecture Notes

These flashcards cover essential vocabulary and concepts from the G-Protein Signaling lecture notes, aiding in the understanding of cell signaling pathways, GPCR function, and associated disorders.

G-Protein Coupled Receptors (GPCRs)

A large family of membrane receptors that transduce signals upon binding with signaling molecules, leading to conformational changes.

• binding of the signaling molecule(ligand) to the GPCR creates a conformational change

• the “on” receptor can cause the G-protein to swap out GDP for GTP, activating it

• the active G-protein can now transmit the signal

Signal Transduction

The process through which a signal from a receptor is relayed through a series of molecular interactions resulting in a cellular response.

Secondary Messenger

Molecules within the cell that transmit the signal from the receptor to alter cell behavior.

Dissociation Constant (Kd)

A measure of the affinity of a receptor for its ligand; a lower Kd indicates a higher binding affinity.

• receptors tend to have a small Kd ( larger denominator than numerator)

• receptors have high affinities for signaling molecules

Autocrine Signaling

A type of signaling where a cell secretes a signal that binds to receptors on its own surface for growth and development.

Paracrine Signaling

Cell signaling where the signaling molecules act on nearby target cells in close proximity.

Endocrine Signaling

Long-distance signaling where hormones are transported through the bloodstream to reach distant target cells.

Negative Feedback Loop

A regulatory mechanism in which the output of a process inhibits or dampens the process itself, maintaining homeostasis.

• product of signal transduction will repress further signaling

• cells can adapt-produce fewer receptors- to overstimulation of a signal pathway

Selective-serotonin reuptake inhibitors (SSRIs)

A class of antidepressants that increase serotonin levels in the synaptic cleft by inhibiting its reuptake.

Epinephrine

A signaling molecule that activates GPCR pathways, leading to various physiological responses including increased heart rate.

G-protein

A molecular switch that transmits signals from GPCRs to

effector proteins, activated by the exchange of GDP for GTP.

• effector protein ( creates response) includes enzymes, transcription factors, ion channels