Cell Signaling and Signal Amplification

A set of flashcards covering key concepts and mechanisms related to cell signaling and signal amplification, especially focusing on second messengers and receptor tyrosine kinases.

What are the two common mechanisms of signal amplification in cell signaling?

Second messengers and phosphorylation cascades.

What role do second messengers play in signal amplification?

They amplify signals by being generated in large quantities in response to an external stimulus.

What is the key difference between second messengers and phosphorylation cascades?

Second messengers are small molecules or ions that act within the cell, while phosphorylation cascades involve a series of phosphorylation events that alter protein activity.

What is the function of adenylyl cyclase in cell signaling?

Adenylyl cyclase converts ATP to cyclic AMP, a second messenger, thereby amplifying the signal.

What is cyclic AMP and how does it function as a second messenger?

Cyclic AMP is a small molecule that binds to target proteins, causing changes in their shape and activity, thus transmitting the signal within the cell.

What is the role of phosphodiesterase in the signaling pathway involving cyclic AMP?

Phosphodiesterase ends the cAMP signaling pathway by breaking down cyclic AMP into AMP, thereby stopping the signal and acting as the limiting factor that controls the duration and intensity of the cellular response.

How do G protein-coupled receptors (GPCRs) activate their associated G proteins?

When bound to GTP, G proteins change shape and become active, acting as a switch to alter the activity of target proteins.

What role does calcium play in cell signaling?

Calcium acts as a second messenger by moving from the endoplasmic reticulum into the cytosol, influencing various cellular processes.

What distinguishes receptor tyrosine kinases (RTKs) from G protein-coupled receptors?

RTKs dimerize in response to a ligand and have intrinsic kinase activity to phosphorylate tyrosines, whereas GPCRs rely on heterotrimeric G proteins for signaling.

What is the significance of phosphorylation in signaling pathways involving receptor tyrosine kinases?

Phosphorylation can activate or inhibit target proteins and create binding sites for other signaling molecules.