BRAF

BRAF
Name	BRAF
Uniprot	P15056
Chromosome	7q34
Length	766 aa

BRAF BRAF is a serine/threonine-protein kinase in the RAF family that functions as a key node in MAPK signaling cascades controlling cell proliferation, differentiation, and survival. Discovered through oncogene screens, it links activated receptor tyrosine kinases and RAS proteins to the MEK–ERK kinase module and plays roles in developmental processes and oncogenesis. Research on BRAF intersects with clinical oncology, molecular genetics, and targeted drug development.

Introduction

BRAF encodes a protein kinase that participates in the RAF–MEK–ERK pathway alongside RAF paralogs and upstream effectors like Epidermal growth factor receptor, KIT, MET and downstream effectors such as MAP2K1 and MAPK1. It was identified in screens related to v-raf retrovirus studies and later linked to human cancers discovered in projects at institutions including Sanger Institute and Cold Spring Harbor Laboratory. BRAF signaling is modulated by interactions with small GTPases (notably KRAS, NRAS, HRAS) and scaffold proteins studied in labs at universities such as Harvard University and Stanford University.

Structure and Function

The protein comprises conserved domains found in RAF kinases: an N-terminal regulatory region with a Ras-binding domain and a C-terminal kinase domain homologous to protein kinases studied in Protein Data Bank entries and structural work from European Molecular Biology Laboratory. Structural studies used crystallography methods developed at Max Planck Institute and revealed activation segment conformations important for catalytic function. BRAF phosphorylates MAP2K1 (MEK1) and MAP2K2 (MEK2), which then activate MAPK1 (ERK2) and MAPK3 (ERK1), creating transcriptional outputs mediated by factors such as ELK1, FOS and MYC. BRAF activity is regulated by dimerization dynamics explored in collaborations between groups at Yale University and Massachusetts Institute of Technology.

Genetics and Regulation

The BRAF gene is located on chromosome 7q34 and exhibits alternative splicing forms catalogued by databases like Ensembl and UniProt. Germline and somatic variants arise from mutational processes examined in consortia such as The Cancer Genome Atlas and International Cancer Genome Consortium. Oncogenic mutations cluster in regions analogous to those characterized in kinase domain studies by researchers at University of Cambridge and Johns Hopkins University. Regulatory control involves phosphorylation by upstream kinases, interactions with 14-3-3 proteins identified in proteomics studies from EMBL-EBI, and modulation by ubiquitin ligases researched at University of California, San Francisco. Developmental syndromes linked to germline mutations were characterized in clinical genetics centers including Great Ormond Street Hospital.

Clinical Significance and Diseases

Oncogenic BRAF mutations, especially the recurrent V600 substitution, are implicated in cancers such as melanoma, colorectal cancer, papillary thyroid carcinoma, and subsets of non-small cell lung carcinoma. These associations were delineated in epidemiological and molecular pathology studies at institutions like Memorial Sloan Kettering Cancer Center and MD Anderson Cancer Center. Germline variants cause developmental disorders classified in clinical literature from Boston Children's Hospital and research coordinated by European Society of Human Genetics. BRAF alterations also appear in rare histiocytic disorders described in case series from specialty centers including Mayo Clinic.

Diagnostic Testing and Biomarkers

Detection of clinically relevant BRAF variants uses assays developed by diagnostic companies and academic labs, including PCR-based tests, allele-specific assays piloted at Mayo Medical Laboratories, and next-generation sequencing panels implemented at Broad Institute and Foundation Medicine. Immunohistochemistry with mutation-specific antibodies and liquid biopsy approaches using circulating tumor DNA were validated in multicenter trials coordinated by groups at Dana-Farber Cancer Institute and University of Texas MD Anderson Cancer Center. Biomarker strategies integrate BRAF status with co-alterations in genes like PTEN, TP53, PIK3CA and expression signatures curated by Gene Expression Omnibus.

Therapeutic Targeting and Inhibitors

Small-molecule BRAF inhibitors were developed following lead discovery programs in pharmaceutical companies such as Roche, GlaxoSmithKline and Novartis and advanced through clinical trials at centers including National Institutes of Health. First-generation ATP-competitive inhibitors produced dramatic responses in BRAF-mutant melanoma but also paradoxical activation in RAS-mutant contexts, prompting combination strategies with MEK inhibitors from companies like Genentech and Array BioPharma and trials run by cooperative groups such as EORTC and SWOG. Resistance mechanisms—secondary mutations, pathway reactivation, and phenotype switching—were elucidated in studies from University of California, San Diego and translated into next-generation inhibitors and combination regimens tested at Royal Marsden Hospital and University College London.

History and Research Developments

Key milestones include initial identification of RAF oncogenes in viral models at Sanger Institute collaborators, cloning of the human gene in laboratories at Cold Spring Harbor Laboratory, and the discovery of the V600 mutation in melanoma by teams at Institute Curie and Vanderbilt University. Large-scale genomic projects like The Cancer Genome Atlas mapped BRAF alterations across tumor types, guiding precision oncology initiatives at institutions such as Memorial Sloan Kettering Cancer Center and Mayo Clinic. Ongoing research explores non-canonical functions, isoform-specific regulation, and therapeutic resistance addressed in consortia including AACR and ASCO meetings.

Category:Human proteins