Signal Transduction Flashcards
What are signalling networks?
Signalling networks involve signals on the outside of a cell being sensed by receptor tyrosine kinases or other proteins through the binding of growth factors or ligands.
What happens when a growth factor binds to a receptor?
It causes a conformational intracellular change in the receptor, setting off an intracellular signalling cascade that affects transcription factors and gene expression.
What are growth factors?
Polypeptides that are primary mediators of intracellular communication, released from cells or organs to direct cells to act in a particular way.
What are hormones?
Hormones act at a distance.
What are paracrine factors?
Paracrine factors act locally.
What are juxtacrine factors?
Juxtacrine factors act through cell-cell contact.
What are autocrine factors?
Autocrine factors act on the same cell.
What are intracrine factors?
Intracrine factors act intracellularly.
What are growth factor receptors?
They can be normal type/wild type or have oncogenic mutations that induce activation in a ligand-independent manner.
What is the effect of oncogenic mutations in growth factor receptors?
They can cause inappropriate activation of downstream proteins or transcription factors.
What is phosphorylation?
The transfer of a high-energy phosphate group from ATP or GTP to a protein, catalyzed by kinases, altering the protein’s conformation.
What initiates the intracellular signalling cascade?
Ligand binding to the extracellular ligand binding domain causes receptor dimerization and autophosphorylation, activating the intracellular tyrosine kinase domain.
What is the role of PKC in the phosphatidylinositol pathway?
PKC acts downstream as a node in multiple pathways regulating cancer and stem cell phenotypes.
What does AKT do?
AKT promotes survival, proliferation, and cell growth by phosphorylating various substrates.
What is the role of mTOR?
mTOR is a key node in metabolism, regulating protein synthesis and allowing cell size increase and division.
