What is the Difference Between Upregulation and Downregulation

The main difference between upregulation and downregulation is that upregulation is the process of increasing cellular components such as proteins and RNA. In contrast, downregulation is the process of decreasing cellular components.

Upregulation and downregulation are two processes critical in cellular activities. Both processes occur in response to external and internal stimuli.

Key Areas Covered

1. What is Upregulation
– Definition, Features, Function
2. What is Downregulation
– Definition, Features, Function
3. Similarities Between Upregulation and Downregulation
– Outline of Common Features
4. Difference Between Upregulation and Downregulation
– Comparison of Key Differences

Key Terms

Downregulation, Upregulation

What is Upregulation

Upregulation is the increase in the number of cellular components in response to stimuli. For example, liver cells increase the production of cytochrome P450 enzymes when exposed to xenobiotic compounds such as dioxin. This decreases the number of dioxin molecules. On the other hand, epigenetic alterations are responsible for both, the upregulation and downregulation of RNA and proteins. It may cause the expression of some RNA and proteins while downregulating other RNA or proteins.

Figure 1: Cytochrome P450 Enzyme

Furthermore, all living organisms are capable of receiving signals from the outside of the cell membrane through the receptors that occur on the cell membrane. When a signal interacts with the receptor, the signal can direct the cell to a particular function. Therefore, cells are capable of responding to chemical messengers. Cellular processes can be upregulated through cell signaling. Also, the upregulation of receptors can occur in response to hormones and toxins.

What is Downregulation

Downregulation is the decrease of the cellular content in response to stimuli. Insulin receptor downregulation is an example of downregulation. β-cells of the pancreas secrete insulin hormone. The target cells for the insulin are liver cells. An elevated blood glucose level is the stimulus for the synthesis and secretion of insulin hormone. The hormone binds to the receptors on the liver cells to increase glycogen synthesis from glucose. When the pancreases release a higher concentration of insulin than usual, insulin receptors are downregulated to decrease the insulin response.

Figure 2: Insulin Receptor

Moreover, elevated insulin levels in the bloodstream signal the downregulation of the insulin receptors. Meanwhile, the binding of insulin to the insulin receptor on the cell membrane results in the endocytosis of the receptor-ligand complex. This internalization of the insulin molecules results in the degradation of the insulin hormone, downregulating the number of receptors on the cell membrane for insulin.

Similarities Between Upregulation and Downregulation

• Upregulation and downregulation are two processes that occur in cells.
• They occur in response to various stimuli.
• They are essential in various cellular processes.

Difference Between Upregulation and Downregulation

Definition

Upregulation refers to the process by which a cell increases in amounts of cellular components, such as RNA and proteins, in response to an external stimulus. In contrast, downregulation refers to the decrease in the production and quantities of its cellular components.

Significance

Upregulation increases the cellular components, while downregulation decreases the cellular components.

Importance

Upregulation is essential in cell division, while downregulation is necessary for receptor downregulation.

Conclusion

In brief, upregulation and downregulation are two types of processes that change the number of cellular components. They are essential in different cellular processes. Upregulation is the increase of cellular components in response to external stimuli. It is crucial in cell division. In comparison, downregulation is the decrease of cellular components in response to stimuli. Receptor downregulation is an example of downregulation. The main difference between upregulation and downregulation is the change in the number of cellular components.

References:

1. Danielsson F, Skogs M, Huss M, Rexhepaj E, O’Hurley G, Klevebring D, Pontén F, Gad AK, Uhlén M, Lundberg E. Majority of differentially expressed genes are down-regulated during malignant transformation in a four-stage model. Proc Natl Acad Sci U S A. 2013 Apr 23;110(17):6853-8. doi: 10.1073/pnas.1216436110. Epub 2013 Apr 8. Erratum in: Proc Natl Acad Sci U S A. 2015 Dec 22;112(51):E7158. PMID: 23569271; PMCID: PMC3637701.

Image Courtesy:

1. “Cytochrome P450 Oxidoreductase aus 2BN4 pdb” By B.Kleine – Own work (CC-BY SA 3.0) via Commons Wikimedia
2. “Insulin glucose metabolism” By User Meiquer – Own Work (CC-BY SA 3.0) via Commons Wikimedia