Chapter 15: Signaling at the Cell Surface

Flashcards based on key concepts from Chapter 15: Signaling at the Cell Surface.

Signal transduction

The process by which one cell type synthesizes a signaling molecule that initiates a specific response in a target cell.

Ligand

A signaling molecule that binds to a receptor on the cell surface.

GPCR (G Protein Coupled Receptors)

A large family of receptors that activate G proteins and are involved in signal transduction.

Second messenger

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

Autocrine signaling

A type of signaling where cells respond to signals they secrete themselves.

Paracrine signaling

A type of signaling where the secreted molecules act on nearby target cells.

Endocrine signaling

A type of signaling where hormones are secreted into the bloodstream to act on distant target cells.

Adenylyl cyclase

An enzyme that converts ATP to cyclic AMP (cAMP), a second messenger.

Phospholipase C

An enzyme that produces inositol trisphosphate (IP3) and diacylglycerol (DAG) from phosphatidylinositol, both of which are second messengers.

GTP-binding proteins

Proteins that act as molecular switches in signal transduction, being activated by GTP and inactivated by GDP.

CAMP (Cyclic adenosine monophosphate)

A second messenger important in many biological processes including the activation of protein kinase A (PKA).

Calmodulin

A calcium-binding messenger protein that mediates various aspects of calcium signaling.

Glycogenolysis

The breakdown of glycogen to glucose, regulated by signaling pathways involving cAMP.

Desensitization

The process by which a cell reduces its response to a signaling molecule after prolonged exposure.

Phosphatase

An enzyme that removes a phosphate group from a molecule, often reversing the action of kinases.

Phosphatidylinositol (PI)

A membrane phospholipid that serves as a precursor for second messengers like IP3 and DAG.

Transcription factor

Proteins that regulate the transcription of specific genes by binding to nearby DNA.

Glycogen Synthase

An enzyme that catalyzes the synthesis of glycogen from glucose.

Effector proteins

Proteins that execute the responses in a signal transduction pathway, often being activated by second messengers.

Receptor Tyrosine Kinases (RTKs)

A family of cell surface receptors that, when bound by a ligand, dimerize and phosphorylate tyrosine residues.

Cytokines

Signaling molecules that facilitate communication between cells, especially in immune responses.

Transducin

A G protein that mediates the effect of light on rod cells in the retina.