Cell Signalling Flashcards
Why do cells need to communicate?
Voluntary movement, homeostasis, process information (e.g sight and sound), self preservation (e.g reflexes and sympathetic nervous system).
What is endocrine signalling?
When a hormone travels within the blood to distant target cell.
What is paracrine signalling?
A signal is released to act on an adjacent cell.
What is signalling between membrane attached proteins?
Plasma membrane proteins interacting with each other. Generally involved in immunology.
What is autocrine signalling?
Signalling molecule that is released from a cell and acts on that same cell. Generally leads to negative feedback.
What is an ionotropic receptor?
Ligand gated ion channel. Ligand binds and ion permeable pores open to allow ion to travel down the channel.
What is a g protein coupled receptor?
Ligand binding activates intracellular g protein. This can leads to a response within the cell.
How does a g protein coupled receptor specifically work?
Ligand binding causes conformational change in 7tm receptor. This allows heterotrimeric g protein to bind to 7tm receptor. GDP is exchanged for GTP and g protein is seperated into alpha and beta sub unit. Each sub unit binds to its target protein.
How can g protein be deactivated?
Dephosphorylation of GTP to form GDP. Alpha unit leaves target protein and rejoins with beta unit.
What deactivates 7tm receptor?
Unbinding of ligand. Receptor remains active as long as ligand is bound and can activate further heterotrimeric g proteins.
How do enzyme linked receptors work specifically?
Ligand binding causes receptors to cluster. This leads to enzyme activity within the cell. Enzymes phosphorylate the receptor. This leads to binding of signalling proteins to cytoplasmic domain of receptor. These signalling proteins lead to a signal cascade within the cell.
How do type 1 intracellular receptors work specifically?
Receptor located in cytoplasm. Hormone passes through cell membrane and bind to receptor which leads to heat shock protein dissociation which results in 2 hormone bound receptors join together and form a hormodimer that passes through nucleus and bind to DNA.
What is the difference between type 1 and type 2 intracellular receptors.
Type 1 receptors are found in the cytoplasm while type 2 are found in the nucleus.
How do type 2 intracellular receptors work?
Binding of hormone to DNA receptor. Transcriptional regulation induced.
