What role does protein kinase play

Protein kinase

1 definition

Protein kinases are a group of enzymes that phosphorylate certain proteins. While consuming ATP, they attach a phosphate residue to a protein that has an OH group. Protein kinases belong to the phosphotransferases (EC class 2.7).

2 background

More than 500 different protein kinases are known in humans. The entirety of all protein kinases is also known as the kinome. The catalytic center of most protein kinases is highly conserved.

3 regulation

Since protein kinases have strong effects on cell metabolism due to their central role in signal transduction, their activity is extensively regulated. The substances or regulatory mechanisms that switch protein kinase on and off include:

In addition, the activity of some protein kinases also depends on their precise location within the cell.

4 classification

There is a large number of protein kinases that can be divided into directed and multifunctional protein kinases. The directed kinases can only phosphorylate a specific protein or only very similar proteins, while the multifunctional ones can do this with many different proteins. In addition, the protein kinases can be roughly divided into:

4.1 Serine / Threonine Kinases

Serine / threonine kinases phosphorylate the hydroxyl groups of the amino acids serine and threonine. They include:

4.2 tyrosine kinases

Tyrosine kinases phosphorylate the amino acid tyrosine. They serve primarily as receptors for growth factors and can be further divided into receptor tyrosine kinases (RTKs), receptor-associated tyrosine kinases (RATKs) and non-receptor tyrosine kinases (nRTKs). Examples are:

4.3 Mixed kinases

Some protein kinases are bispecific and can phosphorylate both serine / threonine and tyrosine residues. Examples are MAP2K1 and MAP2K2.