RAF1

RAF1 Full Name

v-raf-leukemia viral oncogene 1

RAF1 Introduction

RAF1, standing for v-raf-leukemia viral oncogene 1, is a serine/threonine protein kinase that functions as a pivotal mediator in the RAS–RAF–MEK–ERK signaling cascade, a highly conserved pathway that transmits extracellular growth factor and mitogenic signals to the nucleus to regulate gene expression. As the cellular homolog of the viral raf oncogene, RAF1 binds directly to activated RAS-GTP at the plasma membrane, undergoes conformational activation, and phosphorylates downstream dual-specificity kinases MEK1/2, which in turn activate ERK1/2 kinases involved in proliferation, differentiation, survival, and migration. This kinase integrates signals from receptor tyrosine kinases, hormones, and stress responses, making it a central node in cell-fate decision processes under physiological conditions.

Figure 1. RAF fusion genes in prostate and gastric cancer and melanoma.(Sources: McMahon M., 2010)

Functionally, RAF1's kinase activity influences a broad range of cellular programs beyond simple proliferation. Through the MAPK cascade, RAF1 helps regulate the cell cycle, apoptotic thresholds, and cytoskeletal dynamics, while also intersecting with pathways such as NF-κB and AKT to impact survival and metabolic adaptation. For example, RAF1 can phosphorylate and inhibit pro-apoptotic factors, affect Rho signaling and migration, and mediate responses to hormonal cues such as follicle-stimulating hormone in steroidogenic tissues. Its regulatory complexity is underscored by multiple phosphorylation sites, interactions with scaffolding proteins such as 14-3-3, and dimerization with other RAF family members like BRAF, which modulates signaling output.

Clinically, dysregulated RAF1 activity has strong disease relevance. Germline RAF1 mutations are well-established causes of RASopathy syndromes including Noonan syndrome and LEOPARD syndrome, which feature congenital heart defects, growth abnormalities, and distinctive craniofacial features arising from aberrant MAPK signaling. Somatic RAF1 alterations, overexpression, and gene fusions have been identified in various cancers, driving MAPK pathway hyperactivation and contributing to tumor growth, survival, and treatment resistance; RAF1 fusions have also been described as oncogenic drivers in rare pediatric sarcomas. Additionally, mutations in RAF1 have been linked to cardiomyopathy through altered kinase activity affecting AKT signaling. Beyond cancer and developmental disorders, RAF1 activity has been implicated in viral replication processes, such as cytomegalovirus infection, where its modulation of host signaling influences viral propagation, highlighting RAF1's broader impact on human health and its emergence as a target for therapeutic intervention.

Alternate Names for RAF1

RAF1; v-raf-leukemia viral oncogene 1; RAF proto-oncogene serine/threonine-protein kinase; cRaf; C-RAF; raf-1; proto-oncogene c-RAF; v-raf-1 murine leukemia viral oncogene homolog 1; murine leukemia viral (v-raf-1) oncogene homolog 1 (3611-MSV);

• 1. McMahon M. RAF translocations expand cancer targets. Nat Med. 2010, 16(7):749-50.