G Protein-Coupled Receptors II

These flashcards cover key vocabulary terms and concepts related to G Protein-Coupled Receptors and their signaling mechanisms as presented in the lecture.

G Protein-Coupled Receptors (GPCRs)

A large family of membrane receptors that transmit signals inside cells upon binding with a ligand.

Adenylyl Cyclase

An effector protein that catalyzes the conversion of ATP to cyclic AMP (cAMP).

Cyclic AMP (cAMP)

A second messenger that transmits signals from GPCRs to downstream effectors.

Phospholipase C (PLC)

An enzyme that hydrolyzes inositol phospholipids to generate inositol triphosphate (IP3) and diacylglycerol (DAG), two important second messengers.

Inositol Triphosphate (IP3)

A second messenger that binds to IP3 receptors to release calcium from the endoplasmic reticulum.

Diacylglycerol (DAG)

A lipid second messenger that, along with Ca2+, activates protein kinase C (PKC).

Calmodulin

A calcium-binding protein that, upon binding to Ca2+, activates various target proteins, including CaM-kinase II.

CaM-kinase II

An enzyme activated by the Ca2+/calmodulin complex that regulates various signaling pathways in cells.

Myosin Light Chain Kinase (MLCK)

An enzyme that phosphorylates myosin light chains, leading to muscle contraction.

Myosin Light Chain Phosphatase (MLCP)

An enzyme that dephosphorylates myosin light chains, resulting in muscle relaxation.

Protein Kinase C (PKC)

An enzyme that regulates smooth muscle contraction and interacts with several signaling pathways.

Phototransduction

The process by which light photons are converted into electrical signals in the retina.

Rod Cells

Photoreceptor cells in the retina that are highly sensitive to light, enabling vision in dim conditions.

Cone Cells

Photoreceptor cells that function in bright light and are responsible for color vision.

cGMP Phosphodiesterase (PDE)

An enzyme that hydrolyzes cGMP to 5'-GMP, involved in the signaling cascade during light perception.

Glutamate

A neurotransmitter released by rod cells that plays a crucial role in transmitting signals to bipolar cells.

On-Center Bipolar Cells

Bipolar neurons that depolarize in response to decreased glutamate, facilitating vision in light.

Off-Center Bipolar Cells

Bipolar neurons that depolarize in response to increased glutamate, facilitating vision in darkness.

Adrenaline (Epinephrine)

A hormone that acts as a ligand for α1-adrenergic receptors, triggering a signaling cascade for smooth muscle contraction.

Gqα

A type of G protein that couples with α1-adrenergic receptors and activates phospholipase C.

Vasoconstriction

The narrowing of blood vessels resulting from smooth muscle contraction, often regulated by Gqα-coupled signaling.

Hyperpolarization

A change in a cell's membrane potential that makes it more negative, often inhibiting action potentials.