Son of Sevenless Proteins

**Definition:** A class of RAS GUANINE NUCLEOTIDE EXCHANGE FACTORS that are genetically related to the Son of Sevenless gene from DROSOPHILA. Sevenless refers to genetic mutations in DROSOPHILA that cause loss of the R7 photoreceptor which is required to see UV light.

**Tree numbers:** - D12.644.360.325.300.700.700 - D12.776.476.325.300.700.700

**Synonyms:** - Son of Sevenless Protein - SOS Proteins