Dear all, I have seen in many research papers that scientists study the expression of a gene in the modified stated as well as in the phosphorylated state after a specific treatment. Can anyone explain the reason for this? and what information this can convey? Many thanks! I have attached a figure for reference.
Start with the basic concepts of protein function then you will understand why the phosphorylation state of a protein is important.
http://www.nature.com/scitable/topicpage/protein-function-14123348
Start with the basic concepts of protein function then you will understand why the phosphorylation state of a protein is important.
http://www.nature.com/scitable/topicpage/protein-function-14123348
Hi Udesh,
In the figure you attached, they are looking at phosphorylated ERK and comparing it to total ERK protein levels. Hence, they are studying phosphorylation of a protein and not of a gene. These are called post-translational modifications as in modifications that happen after translation of a particular gene. You have to look at it in this way: You have the total pool of proteins (in this case ERK), from this pool of protein, a certain fraction or ratio is getting phosphorylated; phosphorylation of ERK indicates its activation. Similarly, AKT and p-AKT; p53 and p-p53, p21 and p-21... etc
Phosphorylation can lead to activation or inhibition of the effector. Phosphate is added by protein kinases and removed by phosphatases. Phosphorylation controls metabolic enzymes, cell motility, membrane channels, assembly of the nucleus and cell cycle progression.
Examples of activation by phosphorylation: ERK, AKT,...
Examples of inhibition by phosphorylation: CDK phosphorylation, or PKA phosphorylates and inhibits MLCK (myosin light chain kinase) by reducing its affinity to substrate
hope this helps,
Patrick
Phosphorylation plays critical roles in the regulation of many cellular processes including cell cycle, apoptosis, growth and signal transduction pathways. Phosphorylation is the most common mechanism of regulating protein function and transmitting signals throughout the cell. While phosphorylation has been observed in bacterial proteins, it is considerably more pervasive in eukaryotic cells. It is estimated that one-third of the proteins in the human proteome are substrates for phosphorylation at some point.
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