LYPD6B

The protein was discovered for the first time in a 2009 study; its presence was detected in the cytoplasm and it was associated with activation of the AP-1 transcription factor.^[8] LYPD6B is known as a prototoxin due to its structural similarity with the 3-fingered snake venom proteins α-bungarotoxin and cobratoxin.^[9] As a prototoxin, LYPD6B also belongs to the protein family of Ly-6/urokinase plasminogen activator receptor (Ly6/uPAR). It has a 3-fingered motif secondary structure which appears due to the presence of 8–10 cysteine residues that facilitate disulfide bond formation.^[9]

The protein is expressed in the nervous system where it acts as an enhancer of the activity of the neurotransmitter acetylcholine certain α7-containing nicotinic acetylcholine receptors, which have a role in learning.^[9] A duplication of the gene has been detected in a case study of two individuals with severe intellectual disability, suggesting its role in proper brain development and cognitive function.^[10] Additionally, the protein demonstrates high expression in several other normal organs including the testis, lungs, stomach, and prostate.^[11]

Hypermethylation of the gene and a subsequent decreased expression has been demonstrated as one of the contributors to the invasive capacity of cancer cells in melanoma.^[12]

The protein LYPD6 also leads to an increase in Wnt/β-catenin signaling.^[7]