Signal Transduction: IP3, DAG and PKC Overview

Signal Transduction

Process of transmitting signals within cells.

Second Messenger

Intracellular molecules activating target proteins.

Effector Enzyme

Enzyme generating second messengers.

G Protein-Coupled Receptors

Membrane proteins activating intracellular signaling.

Adenylyl Cyclase

Enzyme converting ATP to cAMP.

cAMP

Cyclic AMP, a key second messenger.

Phospholipase C

Enzyme producing IP3 and DAG from phospholipids.

IP3

Inositol trisphosphate, mobilizes calcium from ER.

DAG

Diacylglycerol, activates Protein Kinase C.

Protein Kinase C

Enzyme activated by DAG for signaling.

CREB

Transcription factor activated by cAMP signaling.

Gluconeogenesis

Synthesis of glucose from non-carbohydrates.

p-CREB

Phosphorylated CREB, enhances gene transcription.

Glucagon

Hormone increasing blood glucose levels.

Epinephrine

Hormone stimulating fight-or-flight response.

Gs Protein

Stimulates adenylyl cyclase to increase cAMP.

Gi Protein

Inhibits adenylyl cyclase to decrease cAMP.

Gq Protein

Activates PLCβ to produce IP3 and DAG.

G12/13 Proteins

Activate small G proteins, linked to proliferation.

Rhodopsin

Light-sensitive receptor in rod cells.

Transducin

G-protein activated by rhodopsin.

cGMP Phosphodiesterase (PDE)

Enzyme that converts cGMP to GMP.

cGMP

Second messenger that regulates ion channels.

Bradyopsia

Slow vision due to RGS9 mutations.

RGS9

Protein that inactivates transducin in light.

Phospholipase C (PLC)

Enzyme that cleaves PIP2 into IP3 and DAG.

Inositol Trisphosphate (IP3)

Second messenger that releases calcium from ER.

Diacylglycerol (DAG)

Second messenger that activates protein kinase C.

Phosphatidylinositol (PI)

Lipid precursor for second messengers IP3 and DAG.

PIP2

Phosphatidylinositol 4,5-bisphosphate, substrate for PLC.

Gαt

G-protein subunit involved in phototransduction.

Calcium Channels

Ion channels regulated by IP3 signaling.

Protein Kinase C (PKC)

Enzyme activated by DAG and calcium.

G12/13

G-proteins associated with cell proliferation.

Phospholipid Kinases

Enzymes that phosphorylate phospholipids.

Phospholipid Phosphatases

Enzymes that dephosphorylate phospholipids.

Membrane Hyperpolarization

Increased negativity of membrane potential.

Na+ and Ca2+ Ion Channels

Channels affected by cGMP levels.

Ligands

Molecules that bind to receptors, activating them.

Cellular Growth

Process regulated by PKC signaling.

Cell Death

Process influenced by PKC activation.

G Protein-Coupled Receptors (GPCRs)

Receptors that mediate cellular responses to signals.

Protein Kinase A (PKA)

Enzyme activated by cAMP, phosphorylates target proteins.

PKC

Protein kinase activated by DAG and calcium.

Ligand

Molecule binding to a receptor to initiate signaling.

Transcription Activation

Process of increasing gene expression via transcription factors.

Calcium Signaling

Cellular process regulated by calcium ion release.

G Protein

Molecular switch activated by GPCRs.

Small G Proteins

Monomeric G proteins involved in signaling pathways.

Hyperpolarization

Increase in membrane potential making it more negative.

Cell Proliferation

Process of cell growth and division.

Visual Center

Brain region processing visual information.

PKA

Protein kinase A, phosphorylates CREB to activate transcription.

cGMP Phosphodiesterase

Enzyme that reduces cGMP levels in cells.

Gq

G protein that activates phospholipase C.

Gs

G protein that stimulates adenylyl cyclase.

Gi

G protein that inhibits adenylyl cyclase.

Calcium Release

Triggered by IP3 binding to smooth ER receptors.

Second Messengers

Intracellular molecules that relay signals.

Visual Signal

Membrane hyperpolarization in response to light.

Ca2+ Signalling

Cellular signaling pathway involving calcium ions.

Intracellular Messengers

Molecules that relay signals within cells.

Muscle Contraction

Triggered by an increase in intracellular Ca2+.

Exocytosis

Process of neurotransmitter release at synapses.

Hormone Secretion

Release of hormones like insulin in response to Ca2+.

T Cell Activation

Ca2+ plays a role in activating immune cells.

Cell Adhesion

Ca2+ aids in cell attachment to extracellular matrix.

Apoptosis

Programmed cell death influenced by Ca2+ levels.

Cytosolic Ca2+ Concentration

Maintained at approximately 0.1 mM for signaling.

Signal:Noise Ratio

Optimal balance for effective cellular signaling.

Calcium Transport Mechanisms

Active transport and sequestration maintain low Ca2+.

Voltage-Activated Ca2+ Channels

Allow Ca2+ entry based on membrane potential.

Calcium Induced Calcium Release (CICR)

Process where Ca2+ release stimulates further release.

Ryanodine Calcium Channels

Respond to Ca2+ to release more calcium.

IP3 Receptors

Calcium release channels sensitive to IP3.

Polyspermy

Condition where multiple sperm fertilize one egg.

Sperm Binding Receptor

Activates GPCR to initiate calcium release.

Cortical Reaction

Calcium influx prevents polyspermy during fertilization.

Perivitelline Space

Area where cortical vesicle contents are released.

Calcium Granules

Release contents to prevent multiple sperm fertilization.