What is the Difference Between ERK1 and ERK2

Dr.Samanthi

2 years ago

The key difference between ERK1 and ERK2 is that ERK1 is a mitogen-activated protein kinase encoded by the MAPK3 gene, while ERK2 is a mitogen-activated protein kinase encoded by the MAPK1 gene.

Mitogen-activated protein kinase (MAPK or MAP kinase) is a type of protein that is specific to amino acids such as serine and threonine. There are several mitogen-activated protein kinases (ERKs, JNKs, P38s). MAPKs are normally involved in signalling cascades in direct cellular responses to a diverse array of stimuli like mitogens, osmotic stress, heat shock, and proinflammatory cytokines. Moreover, they regulate several cellular functions such as proliferation, gene expression, differentiation, mitosis, cell survival, and apoptosis. ERK1 and ERK2 are two isoforms of ERK mitogen-activated protein kinase.

Key Terms

1. Overview and Key Difference
2. What is ERK1
3. What is ERK2
4. Similarities – ERK1 and ERK2
5. ERK1 vs ERK2 in Tabular Form
6. Summary – ERK1 vs ERK2

What is ERK1?

Extracellular signal-regulated kinase 1 (ERK1) is a mitogen-activated protein kinase that is encoded by MAPK3 gene. It is also known as mitogen-activated protein kinase 3 or P44MAPK. ERK1 protein is a member of the mitogen-activated protein kinase family. This protein acts in the signalling cascade that regulates various cellular processes such as proliferation, differentiation, and cell cycle progression in response to various external stimuli. Generally, this kinase is activated by upstream kinases. After activated, it translocates into the nucleus, where it phosphorylates other nuclear targets. ERK1 protein is clinically very significant.

Figure 01: MAPK Pathway

Moreover, it has been identified that the MAPK3 gene, along with IRAK3, is turned off by two microRNAs that were activated after influenza A virus infection of human lung cells. This suggests the importance of ERK1 protein in cellular functions. Furthermore, a recent research study highlighted the significance of the ERK1/2 regulation as a potential therapeutic target for the treatment of tuberous sclerosis (TS).

What is ERK2?

Extracellular signal-regulated kinase 2 (ERK2) is a mitogen-activated protein kinase that is encoded by the MAPK1 gene. This protein is also known as mitogen-activated protein kinase 1 or p42MAPK. ERK2 is a member of the MAP kinase family. Typically, it acts as an integration point for various biochemical signals and is involved in wide various cellular processes like proliferation, differentiation, transcription regulation, and development. This protein kinase is activated after phosphorylation by upstream kinases. After activation, it translocates to the nucleus of the stimulated cells. Later, ERK2 phosphorylates other nuclear targets. Moreover, ERK2 protein contains multiple amino acid sites that are phosphorylated and ubiqutinated.

Figure 02: ERK2

Some research studies have used model organisms to study the function of MAPK1 gene function. An example of such a research study is a knockout mouse line called Mapk1^{tm1a(EUCOMM)Wtsi}. This study proved that mutation of the MAPK 1 gene leads to significant abnormalities. Moreover, mutation of the MAPK1 gene also showed some roles in T cell-dependent antibody production and T cell development. Furthermore, it also identified that MAPK1 gene mutation in neural progenitor cells of the developing cortex leads to a reduction of cortical thickness and reduced proliferation in neural progenitor cells. Clinically, ERK2 protein function is very important as mutations in the MAPK1 gene are implicated in many types of cancer.

What are the Similarities Between ERK1 and ERK2?

ERK1 and ERK2 are two isoforms of ERK mitogen-activated protein kinase.
Both proteins are normally involved in signalling cascades.
These proteins are activated in direct cellular responses to a diverse array of stimuli like mitogens.
Both proteins are involved in regulating cellular processes such as proliferation, differentiation, transcription regulation, and development.
After activation, both proteins translocate to the nucleus and phosphorylate other nuclear targets.
The protein sequences of ERKI and ERK2 are 84% identical.