Protein kinase

A Protein kinase is a type of enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). This process is a crucial aspect of cell signaling and regulates cellular activities such as protein-protein interaction and protein degradation.

Function

Protein kinases play a pivotal role in the regulation of many cellular processes including cell cycle, gene expression, and differentiation. They can become overactive or inactive in many types of cancer, and a number of inhibitors have been developed to control them.

Classification

Protein kinases are classified into broad groups by the substrate they act on: serine/threonine-specific protein kinases, tyrosine kinases, and dual-specificity kinases. They can also be categorized by their function within the signal transduction pathways.

Structure

The structure of protein kinases is largely conserved, with a small, generally N-terminal, lobe that binds adenosine triphosphate (ATP) and a large C-terminal lobe that binds the protein substrate. The two lobes are linked by a hinge region that aligns the lobes in the correct orientation.

Clinical significance

Protein kinases have been identified as a cause of several diseases, such as cancer, inflammation, and neurodegenerative diseases. They are also the target of a number of pharmaceuticals, which inhibit their activity.

See also

• Kinase
• Phosphorylation
• Signal transduction

References

• Protein kinase function
  Protein kinase function
• Inorganic phosphate 3D model
  Inorganic phosphate 3D model
• CaMKII structure
  CaMKII structure