chapter 3 immunology - Receptor-Ligand Interactions & Signaling

What type of interactions usually bind receptors to ligands?

Noncovalent interactions.

What type of bond is least likely between a receptor and ligand?

Covalent bond.

What is affinity?

The strength of an individual receptor-ligand interaction.

What does Kd measure?

The strength of receptor-ligand binding.

How does Kd relate to affinity?

Inversely.

What does a low Kd indicate?

High affinity.

What does a high Kd indicate?

Low affinity.

What is avidity?

The collective strength of all receptor-ligand interactions.

Can multiple low-affinity interactions produce high avidity?

Yes.

What can ligand binding cause a receptor to do?

Change conformation and/or cluster.

What is receptor clustering?

Multiple receptors gathering together after ligand binding.

Why does receptor clustering enhance signaling?

It brings receptors and signaling molecules together.

Can receptor expression change after cell activation?

Yes.

What does changing receptor expression change?

Cell responsiveness to signals.

What is the first step of signal transduction?

Ligand binds receptor.

What happens after ligand binding in the general signaling pathway?

Receptors and signaling molecules cluster.

What is the function of an adaptor protein?

Forms a scaffold for signaling molecules.

What enzyme is commonly activated early in immune signaling?

Tyrosine kinase.

What does a tyrosine kinase do?

Phosphorylates signaling proteins.

What happens to an activated transcription factor?

It enters the nucleus.

What does an activated transcription factor change?

Gene expression.

What is a common early step in many immune signaling pathways?

Tyrosine phosphorylation by kinases.