Signal Transduction and Cell Signaling

These flashcards cover key vocabulary and concepts from the lecture on signal transduction and cell signaling pathways.

Signal Transduction

The process by which cells sense and respond to external signals, leading to physiological responses.

Autocrine signaling

A type of cell signaling in which a cell secretes a signal molecule that binds to receptors on its own surface.

Paracrine signaling

Cell signaling where messenger molecules travel short distances to affect nearby cells.

Endocrine signaling

A signaling mechanism where hormones are produced by endocrine glands and sent through the bloodstream to distant sites.

Primary messenger

The initial signal molecule that binds to a receptor to initiate a signaling cascade.

Secondary messenger

Molecules that relay signals received from receptors to target molecules inside the cell.

Receptor-ligand interaction

The specific binding of a signal molecule (ligand) to its corresponding receptor.

Agonist

A molecule that binds to a receptor and activates it to produce a biological response.

Antagonist

A substance that binds to a receptor without activating it and blocks the action of an agonist.

Phospholipase C

An enzyme that, when activated by a receptor, cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) to produce DAG and IP3.

G Protein-Coupled Receptors (GPCR)

A large family of receptors that sense molecules outside the cell and activate internal signal transduction pathways.

cAMP

Cyclic adenosine monophosphate, a secondary messenger important in many biological processes, including signal transduction.

Calmodulin

A calcium-binding messenger protein that mediates many cellular processes in response to changes in intracellular calcium.

Insulin receptor

A receptor that, when activated by insulin, initiates a signaling cascade that regulates glucose uptake and metabolism.

Glycogen synthase

An enzyme that facilitates the addition of glucose units to form glycogen, activated by insulin signaling.

Protein Kinase A (PKA)

An enzyme activated by cAMP that phosphorylates various target proteins in response to hormone signaling.

Phosphoinositide-3-kinase (PI3K)

An enzyme that phosphorylates inositol lipids, playing a crucial role in cell signaling pathways related to growth and metabolism.

Creb (cAMP response element-binding protein)

A transcription factor activated by cAMP signaling that promotes gene expression.

Adenylyl cyclase

An enzyme that converts ATP to cAMP in response to signaling molecules.

Phosphodiesterase

An enzyme that degrades cAMP, thus turning off the signal pathway.

Calcium oscillations

Fluctuations in calcium ion concentration that encode information for cellular responses.

Feedback inhibition

A regulatory mechanism in which the end product of a pathway inhibits an earlier step to prevent overactivity.

Phosphorylation

The addition of phosphate groups to a protein, which can change the protein’s function and activity.

PKA substrates

Proteins that are phosphorylated by Protein Kinase A, leading to various physiological responses.

Creb activation

A process that involves phosphorylation by PKA leading to increased gene expression.

Cyclic GMP

A secondary messenger similar to cAMP that is involved in signaling pathways, particularly those related to nitric oxide.