Login processing...

Trial ends in Request Full Access Tell Your Colleague About Jove

7.9: Phosphorylation

JoVE Core

A subscription to JoVE is required to view this content. Sign in or start your free trial.


7.9: Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.

During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly phosphorylated amino acids. Accordingly, protein kinases are classified as serine/threonine kinases, tyrosine kinases, or dual action kinases if they can phosphorylate all three amino acids. Conversely, protein phosphatases catalyze the removal of the phosphate group (dephosphorylation), restoring the original properties of the protein.

Under physiological conditions, phosphorylation and dephosphorylation are tightly regulated to prevent prolonged changes in protein structure and function. Disruption of this balance can cause diseases, including cancer and various neurodegenerative disorders. For instance, a protein called tau is hyperphosphorylated in Alzheimer’s disease (AD). Physiologically, tau regulates the shape, structure, and development of neurons. The tau protein contains over 80 serine, threonine, and tyrosine residues, of which only a fraction is usually phosphorylated. In the brains of patients with AD, tau is abnormally and excessively phosphorylated. This alters the solubility of the protein, forming toxic insoluble aggregates that lead to neuronal death.

Suggested Reading


Phosphorylation Phosphate Group Protein Function ATP Hydrolysis Protein Kinases Amino Acid Side Chains Shape Change Protein Activation/deactivation Protein Phosphatases Dephosphorylation Cellular Processes Chemical Modification Protein Structure Protein Activity Protein Stability Protein Localization Protein Interactions Serine/threonine Kinases Tyrosine Kinases

Get cutting-edge science videos from JoVE sent straight to your inbox every month.

Waiting X
Simple Hit Counter