ECRG4 and ocular melanoma: Podvin et al. (2015) found that augurin binds to the endotoxin receptor, after which it is internalized. To probe this possibility in the ME, we co-immunoprecipitated ECRG4 with molecules involved in innate immunity in the middle ear mucosa during OM (TLR2, TLR4, CD14, and MD2). We confirmed that the ∼8 kDa fragment of ECRG4, the only form present in the middle ear during OM, immunoprecipitated with antibodies against TLR4, its co-receptor CD14, and MD2, which together form the lipopolysaccharide (LPS) receptor (Figure 8).