About Protein kinases:
Protein kinases are a group of kinase enzymes found within the human body. The list of roughly 500 protein kinase genes make up about 2% of human genes. The enzymes alter other proteins through a process known as phosphorylation, which is where phosphate groups are added to them.
Protein Kinase Structure
Protein kinases are enzymes located in the cytoplasm that phosphorylates proteins. The chief enzymes consist of PKA, PKG, PKC, and tyrosyl protein kinases. The eukaryotic protein kinases belong to a wide and varied family of proteins that boast a shared conserved catalytic core. The N-terinal of the catalytic domain contains glycine residues close to the lysine amino aid, having an influence on ATP binding Meanwhile, the central region of the catalyic domain has a conserved aspartic acid.
Phosphorylation of the proteins is very quick due to the rapid dephosphorylate of previously phosphorylated cells, resulting in the termination of the intracellular signal. By regulating the biological activity of proteins, the protein kinases induce a change from inactivity to activity within the target cells.
Examples of human proteins including the protein kinase domain include but are not limited to; AAK1, AATK, ARAF, AURKA, AXL, BLK, BMPR1A, BMPR1B, BMX, CAMK4, CDK1, CDK10, CHUK, CIT, DYRK1A, DYRK1B, EGFR, FER, FES, GAK, HUNK, IT, KSR1, KSR2, LCK, LIMK1, LIMK2, MAP2K5, MYLK4, NRK, OXRS1, PLK1, PLK2, POMK, RET, ROCK1, ROCk2, SIK1, SIK2, LK, TEC, TEK, ULK1, ULK2, WEE1, and ZAP70.
Protein Kinase Function and Mechanisms
As the largest enzyme superfamily related to cell signal transduction, protein kinases are therapeutic targets for various diseases. Protein kinases can, through phosphorylation, alter protein functions in several ways. It may increase or decrease the protein’s activity, stabilize it, or even lead to its destruction.
The enzymes can also localize the protein while regulating the enzyme too. Because it is a reversible covalent modifications, prosphorylation is seen to be regulatory. Allosteric control, for example, responds to signals outside of the cell. The phosphorylation is more frequent in eukaryotic cells than prokaryotic cells due to their wider response rate.
Pathways affected by protein kinases include metabolism, cell signalling, protein regulation, cellular transport, secretory processes. Protein kinases will influence both activity and reactivity, as well as binding mechanisms in relation to other molecules.
Protein Kinase Interactions
Roughly 30% of all human proteins can be changed by the protein kinase activities, affecting signal transduction and other cellular pathways. The majority act on both serine and theonine while others interact with tyrosine. Dual-specificity kinases act on all three.Kinases are turned on or off by phosphorylation, having huge impact on the target cell.
The serine and theonine protein kinases phosphorylate the OH group and may be regulated by various events such as DNA damage, as well as chemical signals such as cAMP/cGMP, diacylglycerol, and Ca2+/calmodulin.
Another significant group of protein kinases is the mitogen-activated protein (MAP) kinases. protein phosphatases can limit the activity on the MAP kinases while the activation of transmembrane receptors via natural ligands or crosslinking agents send signals that include oxidant stress.