1 L4 Cell Signalling Pathways 2 Flashcards
Define enzyme-linked receptors
Receptors that are enzymes OR Receptors that are coupled to enzymes
What are the 3 key regions of an enzyme linked receptor
Extracellular domain - Transcellular domain - Intracellular domain
What are the 2 types of intracellular domain. Describe them
Intrinsic enzyme domain
Is bound to a separate enzyme
What kind of receptor is tyrosine kinase
Enzyme-linked receptor
Describe the mechanism of enzyme-linked receptors
Ligands bind monomer (independent) receptors - Receptors dimerise - Cross phosphorylate - Binding and activation of downstream proteins
What are the 2 pathways activated by insulin
PI3K - GLUT 4 channel opens
RAS pathway - transcription
What are the ligands for cytokine receptors
Growth Hormone, Prolactin
True or False- Cytokine receptors have intrinsic enzyme activity
False- they are coupled to an enzyme that phosphorylates
What kind of receptor does the JAK/STAT pathway use
Cytokine receptor
Define an Activator
A protein that binds to a specific region of DNA to promote transcription
Define a Repressor
A protein that binds to a specific region of DNA to suppress transcription
What are the 3 ways to regulate gene expression
Synthesis - Localisation (location) - Activation
When is the signal to proliferate sent to the cell
During G1 phase
Describe what kind of receptors and the role of these in Cell growth and proliferation
It involves activation of cyclin-dependent kinases e.g. serine/threonine kinases that are activated by cyclin. These activate transcription factors that promote entry into S phase
How does the cell control metabolic processes
By increasing uptake and utilisation of nutrients
By regulating enzymes involved in cellular metabolism
What are the 2 pathways that apoptosis can take
Intrinsic and Extrinsic (Death receptor)
