Ch. 6 Signaling Pathways

Cell Signaling

The process by which cells communicate and respond to external stimuli, involving the transmission of signals from the cell membrane to the nucleus.

Transcription Factors (TFs)

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

Immediate Early Genes

Genes that are rapidly activated in response to signaling but do not require new protein synthesis for their expression.

Delayed Early Genes

Genes that require de novo protein synthesis for their expression and are activated after immediate early genes.

Cycloheximide

A drug that inhibits protein synthesis, used to study gene expression patterns.

Serum Starvation

A technique used to study the effects of serum on cells by depriving them of proteins and growth factors, followed by re-addition.

Ras signaling pathway

A key signaling pathway involved in cell proliferation and survival, often mutated in cancers.

Phospho-tyrosines

Phosphorylated tyrosine residues that serve as docking sites for proteins involved in signaling pathways.

SH2 domain

A protein domain that binds specifically to phospho-tyrosine motifs, playing a critical role in signaling pathways.

SH3 domain

A protein domain that recognizes proline-rich sequences in target proteins, facilitating protein-protein interactions.

GAP (GTPase-activating protein)

A protein that stimulates the GTPase activity of RAS, leading to its inactivation.

GEF (Guanine nucleotide exchange factor)

A protein that facilitates the activation of RAS by promoting the exchange of GDP for GTP.

PI3K/AKT pathway

A critical signaling pathway involved in cell growth, proliferation, and survival, frequently altered in cancer cells.

NF-κB (Nuclear Factor kappa-light-chain-enhancer of activated B cells)

A transcription factor that regulates genes involved in immune response, cell survival, and inflammation.

Oncogenic mutations

Mutations that contribute to the transformation of normal cells into cancer cells by altering signaling pathways.

Signal transduction

The process by which a cell responds to external signals through a series of molecular interactions.

Amphipathic molecules

Molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

Raf pathway

A downstream signaling pathway activated by RAS, involved in promoting cell division and survival.

Feedback loops

Regulatory mechanisms in signaling pathways that can enhance or inhibit the signaling effect.

B cell development

The process by which B cells are formed and matured, which NF-κB signaling significantly influences.