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MAP2K2
mitogen-activated protein kinase kinase 2
The MAP2K2 gene provides instructions for making a protein (MEK2) that is an essential component of the RAS/MAPK signalling pathway, which regulates cell growth, differentiation, and survival. MAP2K2 encodes the MEK2 protein kinase, a crucial enzyme within the cellular signalling cascade known as the RAS/MAPK pathway.
MAP2K2 is located on the short (p) arm of chromosome 19, at band 19p13.3. Arm ratio per GRCh38 - banding schematic.
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Overview
The MAP2K2 gene, full name mitogen-activated protein kinase kinase 2, plays a vital role in cellular communication by producing the MEK2 protein kinase. This protein is a key member of the RAS/MAPK signalling pathway, a complex network responsible for transmitting signals from the cell's exterior to its nucleus [PMID:21228399]. These signals orchestrate critical cellular functions such as cell division, specialisation, and programmed cell death (apoptosis).
Dysfunction within the MAP2K2 gene, and consequently the MEK2 protein, can disrupt the finely balanced RAS/MAPK pathway. Such disruptions are associated with a range of conditions, particularly those known as RASopathies, which involve various developmental and physiological abnormalities. MAP2K2's function is relevant to investigating numerous inherited conditions.
What the gene does
The primary function of the MAP2K2 gene is to provide the genetic blueprint for the MEK2 protein kinase. This enzyme acts as an intermediary in the crucial RAS/MAPK signalling pathway, a cascade that processes external cellular stimuli and translates them into specific intracellular responses. In this pathway, MEK2 is activated by upstream RAS-related proteins and, in turn, activates downstream mitogen-activated protein (MAP) kinases, specifically ERK1 and ERK2 [PMID:21228399].
The RAS/MAPK pathway is a master regulator of numerous biological processes. These include cellular proliferation, which is the process of cell growth and division, and cellular differentiation, where cells mature to perform specialised functions. It also influences cell motility and plays a role in apoptosis, the regulated process of cell self-destruction. The MEK2 protein works in close conjunction with MEK1, a protein produced by the MAP2K1 gene, and both appear to be indispensable for normal foetal development and postnatal survival [PMID:11986616]. The intricate regulation provided by MEK1 and MEK2 ensures that cellular responses to external cues are precise and appropriate, maintaining cellular homeostasis.
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Chromosome location
The MAP2K2 gene is situated on chromosome 19, specifically at location 19p13.3. This chromosomal band refers to its precise address on the short arm (p) of chromosome 19. The human genome contains approximately 20,000 to 25,000 genes, and each has a unique position, which helps in identifying and studying their roles in health and disease.
Protein structure
The MEK2 protein, encoded by the MAP2K2 gene, is composed of 400 amino acids. Its structure includes a significant Protein kinase domain, which spans amino acids 72-369. This domain is crucial for the protein's enzymatic activity, enabling it to phosphorylate and activate other proteins in the signalling cascade. Additionally, a Disordered region exists between amino acids 286-310. Disordered regions often have flexible structures that can facilitate interactions with multiple binding partners, which is typical for proteins involved in complex signalling pathways.
Key variants
Genetic variations within the MAP2K2 gene can alter the structure and function of the MEK2 protein, potentially leading to its abnormal activity. These variants can range from single nucleotide changes that modify one amino acid in the protein to larger deletions or insertions. Such changes can disrupt the tightly regulated RAS/MAPK signalling pathway, leading to a variety of clinical manifestations. The impact of a specific variant often depends on its location within the gene and how it affects critical protein domains.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.169T>G | p.Phe57Val | Pathogenic | ★★★☆ | Cardio-facio-cutaneous syndrome |
c.170T>G | p.Phe57Cys | Pathogenic | ★★★☆ | RASopathy |
c.383C>A | p.Pro128Gln | Pathogenic | ★★★☆ | RASopathy |
c.400T>C | p.Tyr134His | Pathogenic | ★★★☆ | RASopathy |
c.169T>C | p.Phe57Leu | Pathogenic/Likely pathogenic | ★★☆☆ | Cardiofaciocutaneous syndrome 4 |
c.181A>G | p.Lys61Glu | Pathogenic/Likely pathogenic | ★★☆☆ | Cardiofaciocutaneous syndrome 4 |
c.183A>C | p.Lys61Asn | Pathogenic/Likely pathogenic | ★★☆☆ | Cardiofaciocutaneous syndrome 4 |
c.376A>G | p.Asn126Asp | Pathogenic/Likely pathogenic | ★★☆☆ | Cardiofaciocutaneous syndrome 4 |
c.383C>T | p.Pro128Leu | Pathogenic/Likely pathogenic | ★★☆☆ | MAP2K2-related disorder |
c.395G>A | p.Gly132Asp | Pathogenic/Likely pathogenic | ★★☆☆ | Cardiovascular phenotype |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Variants in the MAP2K2 gene are associated with several inherited conditions, primarily those classified under the umbrella of RASopathies. These conditions arise from dysregulation of the RAS/MAPK pathway, which can lead to a spectrum of developmental abnormalities affecting multiple organ systems. The precise clinical presentation can vary significantly depending on the specific genetic change in MAP2K2. For instance, at least 13 different MAP2K2 mutations have been identified in individuals with cardiofaciocutaneous syndrome. These genetic alterations predominantly involve single amino acid changes in the MEK2 protein, although some cases show the deletion of multiple amino acids.
No disease links recorded for this gene in our reference set.
Inheritance pattern
Conditions caused by pathogenic MAP2K2 variants typically follow autosomal dominant inheritance.
Each child has a 50% chance of inheriting the pathogenic variant, regardless of sex.
UK clinical status
The MAP2K2 gene is recognised in the UK for its association with several inherited conditions, consistent with its inclusion on multiple NHS Genomic Medicine Service clinical panels. These include 'Childhood solid tumours cancer susceptibility', 'DDG2P', 'Early onset or syndromic epilepsy', 'Foetal anomalies', 'Foetal hydrops', 'Intellectual disability', 'IUGR and IGF abnormalities', 'Monogenic short stature', 'Paediatric or syndromic cardiomyopathy', 'Pigmentary skin disorders', 'Primary lymphoedema', and 'RASopathies'. This broad inclusion highlights its recognised clinical significance within the NHS.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Diet & lifestyle considerations
General lifestyle approaches that support overall health may contribute to wellbeing for individuals with genetic predispositions, but there is no specific lifestyle intervention conclusively shown to prevent or treat conditions associated with MAP2K2 variants. A balanced diet, regular physical activity, and avoiding smoking and excessive alcohol consumption are generally recommended for maintaining good health. These general health guidelines apply to the general population and are not specific medical advice for those with MAP2K2 variants.
Supplement considerations
Currently, there is no conclusive scientific evidence to suggest that specific supplements can prevent or treat conditions associated with MAP2K2 variants. Individuals considering any supplements should consult with a healthcare professional to discuss potential risks, benefits, and interactions with other medications or existing health conditions. Dietary supplements are not regulated with the same rigour as prescription medicines.
Frequently asked questions
What is the MAP2K2 gene?
The MAP2K2 gene provides instructions for creating the MEK2 protein kinase, an enzyme crucial for the RAS/MAPK signalling pathway. This pathway regulates essential cellular functions such as growth, division, and differentiation.
What is the RAS/MAPK signalling pathway?
The RAS/MAPK pathway is a complex cellular communication system that transmits signals from the outside of a cell to its nucleus. It governs vital cellular processes including cell proliferation, differentiation, movement, and programmed cell death.
What conditions are associated with MAP2K2 variants?
Variants in the MAP2K2 gene are primarily associated with a group of developmental disorders known as RASopathies, including cardiofaciocutaneous syndrome. These conditions can affect various organ systems due to the dysregulation of the RAS/MAPK pathway.
How is MAP2K2 relevant to hereditary conditions?
MAP2K2 is classified as an autosomal dominant gene, meaning a single altered copy of the gene can potentially lead to a hereditary condition. Its involvement in developmental pathways makes it relevant for conditions like RASopathies.
Can lifestyle changes help manage conditions related to MAP2K2?
While general healthy lifestyle practices like a balanced diet and regular exercise are beneficial for overall well-being, there is no specific lifestyle intervention scientifically proven to prevent or treat conditions directly linked to MAP2K2 variants. Always consult a healthcare professional for personalised advice.
References
- Narumi Y, Aoki Y, Niihori T. Molecular and clinical characterization of cardio-facio-cutaneous (CFC) syndrome: overlapping clinical manifestations with Costello syndrome. American journal of medical genetics. Part A. 2007. PMID: 17366577
- Scholl FA, Dumesic PA, Barragan DI. Mek1/2 MAPK kinases are essential for Mammalian development, homeostasis, and Raf-induced hyperplasia. Developmental cell. 2007. PMID: 17419998
- Nava C, Hanna N, Michot C. Cardio-facio-cutaneous and Noonan syndromes due to mutations in the RAS/MAPK signalling pathway: genotype-phenotype relationships and overlap with Costello syndrome. Journal of medical genetics. 2007. PMID: 17704260
- Rodriguez-Viciana P, Tetsu O, Tidyman WE. Germline mutations in genes within the MAPK pathway cause cardio-facio-cutaneous syndrome. Science (New York, N.Y.). 2006. PMID: 16439621
- Duesbery N, Vande Woude G. BRAF and MEK mutations make a late entrance. Science's STKE : signal transduction knowledge environment. 2006. PMID: 16569817