lecture 4

These flashcards cover key terms and concepts related to second messengers, their functions, and regulatory mechanisms as outlined in the lecture notes.

cAMP

A crucial second messenger formed from ATP by adenylyl cyclase; regulates various cellular functions.

Phospholipase C

An enzyme that cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol trisphosphate (IP3) and diacylglycerol (DAG), which are important second messengers.

Protein Kinase A (PKA)

An enzyme activated by cAMP that phosphorylates target proteins, affecting various cellular processes.

G-protein Coupled Receptors (GPCRs)

Receptors that activate G proteins and trigger intracellular signaling pathways upon neurotransmitter binding.

Phosphodiesterases (PDEs)

Enzymes responsible for the degradation of cyclic nucleotides like cAMP and cGMP, influencing second messenger signaling.

Calcium ions (Ca2+)

A ubiquitous intracellular messenger involved in various signaling pathways, including muscle contraction and neurotransmitter release.

Adenylyl Cyclase (AC)

An enzyme that converts ATP to cAMP upon activation by Gs protein, playing a key role in second messenger signaling.

Cyclic GMP (cGMP)

A second messenger produced from GTP by guanylyl cyclase, involved in signaling pathways related to nitric oxide.

GTP-binding proteins

Proteins that bind guanosine triphosphate and are key components in transmitting signals from receptors to effectors.

Target Proteins

Proteins that are modified by kinases or phosphatases in response to second messenger signaling.

Epac

Exchange proteins directly activated by cAMP, serving as additional mediators of cAMP signaling.

Heterotrimeric G proteins

G proteins composed of three subunits (α, β, γ) that relay signals from activated GPCRs to effectors.

cAMP Response Element-Binding Protein (CREB)

A transcription factor activated by increases in cAMP or calcium, regulating gene expression.

Insulin Receptor

A receptor that, when activated, triggers a signaling cascade involving phosphoinositide 3-kinase (PI3K) and Akt, promoting glucose uptake.

Guanylyl Cyclase

An enzyme that converts GTP to cGMP, playing a significant role in mediating the effects of nitric oxide.

Diacylglycerol (DAG)

A second messenger produced by the cleavage of PIP2 that activates protein kinase C.

Inositol Trisphosphate (IP3)

A second messenger that facilitates the release of Ca2+ from the endoplasmic reticulum.

Nitric Oxide (NO)

A gaseous signaling molecule that activates guanylyl cyclase, resulting in increased levels of cGMP.

Cyclic AMP (cAMP) pathway

Signaling pathway initiated by the activation of adenylyl cyclase leading to a cascade of cellular responses.

Calmodulin

A calcium-binding messenger protein that mediates calcium signaling by activating various enzymes.