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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed June 2015

What is the official name of the MAP2K1 gene?

The official name of this gene is “mitogen-activated protein kinase kinase 1.”

MAP2K1 is the gene's official symbol. The MAP2K1 gene is also known by other names, listed below.

What is the normal function of the MAP2K1 gene?

The MAP2K1 gene provides instructions for making a protein known as MEK1 protein kinase. This protein is part of a signaling pathway called the RAS/MAPK pathway, which transmits chemical signals from outside the cell to the cell's nucleus. RAS/MAPK signaling helps control the growth and division (proliferation) of cells, the process by which cells mature to carry out specific functions (differentiation), cell movement, and the self-destruction of cells (apoptosis).

The MAP2K1 gene is very similar to a gene called MAP2K2, which provides instructions for making a protein known as MEK2 protein kinase. Like MEK1 protein kinase, this protein functions as part of the RAS/MAPK signaling pathway. Together, the MEK1 and MEK2 protein kinases appear to be essential for normal development before birth and for survival after birth.

How are changes in the MAP2K1 gene related to health conditions?

cardiofaciocutaneous syndrome - caused by mutations in the MAP2K1 gene

At least 12 mutations in the MAP2K1 gene have been identified in people with cardiofaciocutaneous syndrome. Each of these mutations changes a single protein building block (amino acid) in MEK1 protein kinase. These genetic changes abnormally activate the protein, which disrupts the tightly regulated RAS/MAPK signaling pathway in cells throughout the body. The altered signaling interferes with the normal development of many organs and tissues, resulting in the characteristic features of cardiofaciocutaneous syndrome.

Where is the MAP2K1 gene located?

Cytogenetic Location: 15q22.1-q22.33

Molecular Location on chromosome 15: base pairs 66,386,873 to 66,491,544

The MAP2K1 gene is located on the long (q) arm of chromosome 15 between positions 22.1 and 22.33.

The MAP2K1 gene is located on the long (q) arm of chromosome 15 between positions 22.1 and 22.33.

More precisely, the MAP2K1 gene is located from base pair 66,386,873 to base pair 66,491,544 on chromosome 15.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about MAP2K1?

You and your healthcare professional may find the following resources about MAP2K1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the MAP2K1 gene or gene products?

  • Dual Specificity Mitogen-Activated Protein Kinase Kinase 1
  • ERK Activator Kinase 1
  • MAPK/ERK kinase 1
  • MAP Kinase Kinase 1
  • MAPKK1
  • MEK1
  • MEK-1
  • MEK-1 Protein Kinase
  • MKK1
  • MKK1 Protein Kinase
  • MKK-1 Protein Kinase
  • PRKMK1
  • protein kinase, mitogen-activated, kinase 1 (MAP kinase kinase 1)

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding MAP2K1?

amino acid ; apoptosis ; cancer ; cell ; differentiation ; gene ; kinase ; nucleus ; proliferation ; protein ; RAS ; specificity ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Brown NA, Furtado LV, Betz BL, Kiel MJ, Weigelin HC, Lim MS, Elenitoba-Johnson KS. High prevalence of somatic MAP2K1 mutations in BRAF V600E-negative Langerhans cell histiocytosis. Blood. 2014 Sep 4;124(10):1655-8. doi: 10.1182/blood-2014-05-577361. Epub 2014 Jun 30. (
  • Chakraborty R, Hampton OA, Shen X, Simko SJ, Shih A, Abhyankar H, Lim KP, Covington KR, Trevino L, Dewal N, Muzny DM, Doddapaneni H, Hu J, Wang L, Lupo PJ, Hicks MJ, Bonilla DL, Dwyer KC, Berres ML, Poulikakos PI, Merad M, McClain KL, Wheeler DA, Allen CE, Parsons DW. Mutually exclusive recurrent somatic mutations in MAP2K1 and BRAF support a central role for ERK activation in LCH pathogenesis. Blood. 2014 Nov 6;124(19):3007-15. doi: 10.1182/blood-2014-05-577825. Epub 2014 Sep 8. (
  • Duesbery N, Vande Woude G. BRAF and MEK mutations make a late entrance. Sci STKE. 2006 Mar 28;2006(328):pe15. (
  • Narumi Y, Aoki Y, Niihori T, Neri G, Cavé H, Verloes A, Nava C, Kavamura MI, Okamoto N, Kurosawa K, Hennekam RC, Wilson LC, Gillessen-Kaesbach G, Wieczorek D, Lapunzina P, Ohashi H, Makita Y, Kondo I, Tsuchiya S, Ito E, Sameshima K, Kato K, Kure S, Matsubara Y. Molecular and clinical characterization of cardio-facio-cutaneous (CFC) syndrome: overlapping clinical manifestations with Costello syndrome. Am J Med Genet A. 2007 Apr 15;143A(8):799-807. (
  • Nava C, Hanna N, Michot C, Pereira S, Pouvreau N, Niihori T, Aoki Y, Matsubara Y, Arveiler B, Lacombe D, Pasmant E, Parfait B, Baumann C, Héron D, Sigaudy S, Toutain A, Rio M, Goldenberg A, Leheup B, Verloes A, Cavé H. Cardio-facio-cutaneous and Noonan syndromes due to mutations in the RAS/MAPK signalling pathway: genotype-phenotype relationships and overlap with Costello syndrome. J Med Genet. 2007 Dec;44(12):763-71. Epub 2007 Aug 17. (
  • NCBI Gene (
  • Nelson DS, van Halteren A, Quispel WT, van den Bos C, Bovée JV, Patel B, Badalian-Very G, van Hummelen P, Ducar M, Lin L, MacConaill LE, Egeler RM, Rollins BJ. MAP2K1 and MAP3K1 mutations in Langerhans cell histiocytosis. Genes Chromosomes Cancer. 2015 Jun;54(6):361-8. doi: 10.1002/gcc.22247. Epub 2015 Mar 31. (
  • Rodriguez-Viciana P, Tetsu O, Tidyman WE, Estep AL, Conger BA, Cruz MS, McCormick F, Rauen KA. Germline mutations in genes within the MAPK pathway cause cardio-facio-cutaneous syndrome. Science. 2006 Mar 3;311(5765):1287-90. Epub 2006 Jan 26. (
  • Scholl FA, Dumesic PA, Barragan DI, Harada K, Bissonauth V, Charron J, Khavari PA. Mek1/2 MAPK kinases are essential for Mammalian development, homeostasis, and Raf-induced hyperplasia. Dev Cell. 2007 Apr;12(4):615-29. (
  • Scholl FA, Dumesic PA, Khavari PA. Effects of active MEK1 expression in vivo. Cancer Lett. 2005 Dec 8;230(1):1-5. Epub 2005 Jan 18. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: June 2015
Published: November 23, 2015