Cell Signaling

Flashcards to review key vocabulary and concepts related to Cell Signaling.

Cell Signaling

Communication between cells, usually involving a chemical messenger (signal/ligand) released by the signalling cell. The signal is detected by the responding cell via a receptor, triggering intracellular reactions that influence the behavior of the responding cell.

Signal Release

Synthesis and excretion of the signaling molecule.

Signal Detection

Interaction of signal and receptor.

Signal Transduction

Translation of detection to changes in cell physiology or gene expression.

Paracrine Signals

Acts on local set of cells.

Autocrine Signals

Acts on the secreting cell.

Endocrine Signals

Long range signals moving through the blood stream.

Transcription Factors

Cell-cell signalling can change the repertoire of transcription factors in the responding cell, resulting in different gene expression.

Nuclear Receptors

Signals are steroids or retinoids and signals can pass through the plasma membrane.

Nuclear Receptors (Mechanism)

Cytoplasmic proteins, that in their inactive form are bound to Hsp chaperones – Ligand binding releases the Hsp – The receptor-ligand complex moves to the nucleus to activate the transcription of target genes

G-protein linked receptors

Transmembrane receptors are linked to a G-protein, and upon ligand binding the G protein releases GDP and takes up GTP.

Second Messengers (G-protein)

Ga dissociates from Gbg and activates downstream 'second messengers' (eg cAMP).

GTP Hydrolysis

GTP is hydrolysed to GDP and Ga reassociates with Gbg.

Adenylyl cyclase

Active form converts ATP to Cyclic AMP.

Cyclic AMP

Stimulates Protein Kinase A.

Serine/threonine Kinase receptors

Transmembrane receptors that bind the TGFb family of signals. Ligand brings together type I and type II receptors, II phosphorylates I and Smads become phosphorylated and move into the nucleus to act as transcription factors.