 Once activated, TLR9 moves from the endoplasmic reticulum to the Golgi apparatus and lysosomes, where it interacts with MyD88, the primary protein in its signaling pathway.TLR9 is cleaved at this stage to avoid whole protein expression on cell surface, which could lead to autoimmunity.CpG sites are relatively rare (~1%) on vertebrate genomes in comparison to bacterial genomes or viral DNA.