Cell Signalling Flashcards
What is autocrine intercellular signalling?
Cell targets itself.
Synthesis of a soluble ligand that is subsequently released.
What is paracrine intercellular signalling?
Cell targets a nearby cell.
Signalling cell generates and propagates a signal that results in a mediator being released.
What is endocrine intercellular signalling?
A cell targets a distant cell through the bloodstream.
Hormone dependent mechanism
What is exocrine intercellular signalling?
Exocrine glands secrete substances onto an epithelial surface via a duct.
What is juxtacrine intercellular signalling? (AKA direct signalling)
Involves the communication between cells that are in direct contact with each other.
What organ is both an exocrine and endocrine gland?
Liver
What receptor causes a protein conformational change, causing the channel to open allowing ions to move in or out?
Ligand-gated ion channel receptor
What receptor triggers a series of events which induce the binding of G-protein and the modulation of second messengers.
G-protein coupled receptors
What receptor phosphorylate their protein substrates, and are they receptor for many polypeptide growth factors such as insulin?
Kinase-linked receptors
What receptors are intracellular and respond to many hydrophobic ligands which cross the plasma membrane?
Nuclear receptors
Which receptor has the shortest signalling pathway?
Ligand-gated ion channel receptors (milliseconds)
What receptor has the longest time signalling pathway?
Nuclear receptors (hours/days)
What are signalosomes?
Large supramolecular complexes
What is S-Adenosylmethionine (SAM) required for?
SAM is required for DNA methylation
In which biological cycle is SAM synthesized?
Methionine cycle
What is the consequence of low SAM levels on DNA?
Low global DNA hypomethylation
What is a way to measure cell signalling?
Immunoblotting (Western blotting)
What is a key feature of kinase cascades in signal transduction?
Kinase cascades allow different signals to input a pathway at different places.
How do kinase cascades allow signal amplification?
Amplify signals by sequentially activating multiple downstream kinases.
Do signaling cascades involve both kinases and phosphatases?
Yes. Kinases and phosphatases work together.
What role do phosphatases play in kinase cascades?
Phosphatases can turn off or down-regulate kinase cascades by removing phosphate groups.
How can kinase cascades increase specificity in signaling?
Specificity can be increased when kinases are structurally organized within the cascade.
What are the major types of cell signal receptors?
Ligand-gated ion channels
G-protein coupled receptors (GPCRs)
Kinase-linked receptors
Nuclear receptors
Can GPCRs signal from endosomes after receptor internalisation?
Yes
What is an example of a transmembrane receptor capable of activating signal transduction pathways
Integrins
What factors can influence the cellular outcomes of signal transduction?
Cellular outcomes can rely on the signalling molecule lifetime, the type of target cell, and tissue dependency.
True or false. Receptors cannot signal from lipid rafts.
False. Some receptors can signal from lipid rafts.
What are GPCRs and what is their role in cell signalling?
GCPRs are G protein-coupled receptors that mediate signaling by activating G proteins upon ligand binding.
