Exam 2 - Intracellular Signaling Flashcards
What can happen within seconds of IC signaling?
Changes in membrane permeability
What can happen within minutes of IC signaling?
Phosphorylation events
What can happen within hours of IC signaling?
Transcriptional effects
What are the 3 main elements of a signaling pathway?
- Receptor
- Relay/Second messengers/Effectors
- Target protein
What are the 5 classes of cell surface receptors?
- Membrane channels
- GPCRs
- Enzyme-linked receptors
- Pattern recognition receptors
- Cytokine receptors (type of enzyme-linked)
What happens in ion-channel-linked receptor pathways?
Signal molecule (i.e. acetylcholine) binds to receptor and the ion channel opens.
What happens in GPCR pathways?
Signal molecule binds to R, G-protein is activated, enzyme is activated
What happens in enzyme-linked receptor pathways?
Signal molecule in dimer form binds to receptor causing dimerization of receptor; receptors/catalytic domains activate
OR
Signal molecule binds, receptor dimerizes and activates the enzyme
What are pattern recognition receptors important for?
Recognizing foreign invaders
What system are pattern recognition receptors a key part of?
Innate immune system (1st line of defense)
What are toll-like receptors?
Type of pattern recognition receptor that can detect a broad range of pathogens.
What happens in cytokine receptor pathways?
Receptor dimerizes upon binding of a cytokine; cross-phosphorylation of kinases
- Enzyme close but not attached to receptor
What molecule phosphorylates others?
Kinase
What two molecules are exchanged in signaling by phosphorylation?
ATP –> ADP to activate target and vice versa
What two molecules are exchanged in signaling by GTP-binding protein?
GDP –> GTP to activate target and vice versa