Signal transduction pathways often utilize protein phosphorylation/dephosphoryla
ID: 207007 • Letter: S
Question
Signal transduction pathways often utilize protein phosphorylation/dephosphorylation, proteolytic cleavage, or a combination of both mechanisms to elicit a cellular response.
a) Give an example of a pathway that utilizes phosphorylation/dephosphorylation without proteolytic cleavage. (1 pt.)
b) Give an example of a pathway that relies on proteolytic cleavage. (1 pt.)
c) Briefly explain what are the advantages of these two different mechanisms. (2 pts.)
Please just give me the examples for PART a and b. For Part C I need a brief explanation for the advantages of both mechanisms.
Thank you!
Explanation / Answer
a.
receptor tyrosine kinase pathway is a pathway at which phosphorylation and Dephosphorylation occurs.
Kinase is the enzyme which transfers the phosphate group to the tyrosine molecule of the cytosolic portion of the transmembrane protein. Receptor tyrosine kinase pathway involved in the signaling for cell division mainly.
When signal molecule comes then the cytosolic terminal region of the integral membrane protein receptors are phosphorylated by the kinase enzyme.
GPCR signalling pathway: G protein coupled receptors are receptors of cell which are involved in various kind of signaling Pathways.
G protein coupled receptors are the receptors which is associated with G protein. When signal molecule comes then this G protein undergo phosphorylation and then activate the another signaling by the activation of effector protein. The effector protein maybe phospholipase C or any other. which do further signaling process.
b.
The signaling Pathway in which a proteolytic cleavage is involved in the process of signal transduction. Protease activated receptors are the receptors on which protease enzyme acts for proteolytic cleavage. Due to this proteolytic cleavage the extracellular part of the receptor is broken down by the activity of protease enzyme. These receptors are also a G protein coupled receptors. These receptors are present on platelets endothelial cells neuron cells and myocytes. Protease activated receptors are activated by serine proteases such as thrombin and trypsin.
c.
These two different mechanism have different kind of advantages and their specific sections.
For example G protein coupled receptors are present in various cells for multiple different signaling Pathways. The effect of protein and the secondary messengers may be different but the receptors in most of the cell is preferred as G protein coupled receptors.
They are more specific.
They are activated by addition of phosphate hence phosphate amount reduces then it can auto regulate the activation and deactivation process.
The level of secondary control are also available in these receptors.
These are intracellular receptors with specific activation requirements only fulfilled by specific activity of enzyme.
Proteolytic activated receptors are of different importance involved in the digestive systems and the immune system. They have role in cell proliferation enzyme separation and differentiation of cells.
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