Cell Communication

What are the 4 main receptors

Metabotropic, Kinase, Steroid and Ionotropic

What is the function of Ionotropic

Allows flow of ions across membranes

What is the function of Metabotropic

Generates new signals inside cell (2nd Messenger)

What is the function of the Kinase Receptors

Modifies existing molecules to generate new signals

What is the function of the Steroid Receptor

Changes the expression of genes

How do ionotropic receptors work

Binding of ligand to an ionotropic receptor allows the passage of ions down their diffusion gradient

Excitatory Receptors?

Influx of positive charged ions such as Na+ or Ca 2+

Inhibitory Receptors?

Influx of negative charged ions such as Cl-

How do metabotropic receptors work?

They act indirectly to regulate the activity of a plasma membrane target protein, either an enzyme or ion channel

How many subunits do G proteins have?

3- Alpha, Beta and Gamma

How many domain structures do Metabotropic receptors have?

They have a 7 transmembrane domain structure

How does ligand binding affect G protein receptors

They cause the alpha subunut to release GDP for GTP whcih causes the activation of alpha subunit and release of beta/ gamma subunits

What does the activation of alpha subunits result in?

The ability to alter enzyme activities and change the concentration of intracellular signals inside the cell, also known as 2nd messengers

How can metabotropic receptors modifiy ion channels?

By the release of the beta/ gamma subunits

How is signalling from the metabotropic receptors terminated?

By the hydrolysis of GTP to GDP by the alpha subunit