V600E is a

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA replication, DNA or viral repl ...

of the BRAF

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

in which

valine Valine (symbol Val or V) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated −NH3+ form under biological conditions), an α- carboxylic acid group (which is in the deprotona ...

(V) is substituted by glutamic acid (E) at

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

600. It is a driver mutation in a proportion of certain diagnoses, including melanoma,

hairy cell leukemia Hairy cell leukemia is an uncommon hematological malignancy characterized by an accumulation of abnormal B lymphocytes. It is usually classified as a subtype of chronic lymphocytic leukemia (CLL). Hairy cell leukemia makes up about 2% of all leu ...

papillary thyroid carcinoma Papillary thyroid cancer or papillary thyroid carcinoma is the most common type of thyroid cancer, representing 75 percent to 85 percent of all thyroid cancer cases.Chapter 20 in: 8th edition. It occurs more frequently in women and presents in th ...

, colorectal cancer,

non-small-cell lung cancer Non-small-cell lung cancer (NSCLC) is any type of epithelial lung cancer other than small-cell lung carcinoma (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to s ...

Langerhans cell histiocytosis Langerhans cell histiocytosis (LCH) is an abnormal clonal proliferation of Langerhans cells, abnormal cells deriving from bone marrow and capable of migrating from skin to lymph nodes. Symptoms range from isolated bone lesions to multisystem d ...

Erdheim–Chester disease Erdheim–Chester disease (ECD) is an extremely rare disease characterized by the abnormal multiplication of a specific type of white blood cells called histiocytes, or tissue macrophages (technically, this disease is termed a non- Langerhans-c ...

(a non-Langerhans-cell histiocytosis) and

ameloblastoma Ameloblastoma is a rare, benign or cancerous tumor of odontogenic epithelium ( ameloblasts, or outside portion, of the teeth during development) much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack ...

. The mechanism of the mutation is that the negative charge of the acidic glutamic acid residue causes it to be phosphomimetic. This mimics the phosphorylation of the nearby T599 threonine and S602 serine residues in the activation segment of BRAF, which are used to activate the wild type form of the protein. The glutamate residue of the mutant therefore functions to activate BRAF by inhibiting the interaction of the BRAF's glycine rich loop and activation segment, which would ordinarily be inhibitory. The loss of inhibition of BRAF leads to an increase in its basal activity and hence is oncogenic.

Clinical

Vemurafenib Vemurafenib ( INN, marketed as Zelboraf) is an inhibitor of the B-Raf enzyme developed by Plexxikon (now part of Daiichi-Sankyo) and Genentech for the treatment of late-stage melanoma.; The name "vemurafenib" comes from V600E mutated BRAF in ...

, encorafenib, and

dabrafenib Dabrafenib, sold under the brand name Tafinlar & Rafinlar ( both by Novartis) among others, is a medication for the treatment of cancers associated with a mutated version of the gene BRAF. Dabrafenib acts as an inhibitor of the associated enzyme ...

are approved by the

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

for treatment of metastatic melanomas that express V600E.

References

Mutation Tyrosine kinase inhibitors {{2.7-enzyme-stub