Signal Transduction Pathways

Flashcards covering key vocabulary related to signal transduction pathways, their mechanisms, and their implications in biology and medicine.

Signal Transduction Pathways

Chains of events that convert molecular messages into a range of physiological responses.

Transduction

The conversion of information about the presence or concentration of a signal molecule into other forms.

Primary Messenger

The initial signal that is released to initiate signaling.

Response Element

A sequence within a cell's DNA that a signaling molecule activates to result in a physiological change.

Second Messenger

Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules.

Agonist

A ligand that activates receptors.

Adenylate Cyclase

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

Cyclic AMP (cAMP)

A common second messenger involved in the transmission of signals within cells.

Phosphoinositide Cascade

A signaling pathway that involves the cleavage of PIP2 to generate IP3 and DAG.

Calmodulin

A protein that binds calcium ions and modulates the activity of various enzymes.

G-Protein Coupled Receptors (GPCRs)

Large class of cell surface receptors that initiate signaling through G proteins.

Phosphatases

Enzymes that remove phosphoryl groups from proteins, reversing the effects of kinases.

Insulin Signaling

A series of molecular events triggered by the binding of insulin to its receptor.

Protein Kinase A (PKA)

A protein kinase that is activated by cAMP and phosphorylates specific target proteins.

Epinephrine

A hormone that triggers the 'fight or flight' response by binding to adrenergic receptors.

Phospholipase C

An enzyme that cleaves PIP2 into IP3 and DAG, acting in the phosphoinositide cascade.

Diacylglycerol (DAG)

A second messenger that remains in the plasma membrane and activates protein kinase C (PKC).

Cyclic AMP Phosphorylation

The process through which cAMP activates protein kinases to modify target proteins.

Cross-Phosphorylation

A process that activates kinases by phosphorylating each other, often seen in receptor tyrosine kinases.

Intrinsic GTPase Activity

The ability of G protein subunits to hydrolyze GTP to GDP, resetting the signaling pathway.

Cancer and Signal Transduction

Conditions where defects in signaling proteins lead to uncontrolled cell growth.

Monoclonal Antibodies

Therapeutic agents that can inhibit specific signaling pathways activated in tumors.

Imatinib (Gleevec)

A drug that inhibits Abl kinase, used to treat chronic myelogenous leukemia.