Tyrosine kinases

Tyrosine kinases are a subclass of protein kinases that catalyze the transfer of a phosphate group from adenosine triphosphate (ATP) to a tyrosine residue in a protein. This process, known as phosphorylation, is a key event in many cellular processes, including cell division, growth, and death.

Function

Tyrosine kinases play a crucial role in the regulation of cell division and growth, and are important mediators of the signaling cascade. The activity of these enzymes can be affected by mutations, leading to a variety of diseases, including cancer.

Classification

Tyrosine kinases can be classified into two main groups: receptor tyrosine kinases (RTKs) and non-receptor tyrosine kinases (NRTKs).

Receptor tyrosine kinases (RTKs) are located at the cellular membrane and are activated by the binding of extracellular ligands, such as growth factors, hormones, and cytokines. This binding leads to a series of events, including the autophosphorylation of the RTK and the activation of signal transduction pathways.

Non-receptor tyrosine kinases (NRTKs) are located in the cytoplasm and can be activated by a variety of mechanisms, including by the binding of intracellular proteins and by the action of other protein kinases.

Role in Disease

Abnormalities in tyrosine kinases can lead to a variety of diseases. For example, mutations in the genes encoding these enzymes can lead to the development of cancers. In addition, overactivity of tyrosine kinases can lead to the development of autoimmune diseases, such as rheumatoid arthritis and lupus.

Therapeutic Target

Due to their role in disease, tyrosine kinases have become important targets for therapeutic intervention. Several drugs that inhibit the activity of these enzymes, known as tyrosine kinase inhibitors, have been developed and are used in the treatment of various types of cancer.

See Also

• Protein kinase
• Phosphorylation
• Receptor tyrosine kinase
• Non-receptor tyrosine kinase
• Tyrosine kinase inhibitor