Unc-93 Homolog B1 (UNC93B1)

UNC93B1 is an endoplasmic reticulum protein with 12 membrane-spanning domains involved in Toll-like receptor activation. The deduced 597-amino acid protein has a calculated molecular mass of 66 kD and shows significant similarities to the C. elegans unc93 protein. It contains multiple potential membrane-spanning domains and displays some similarities to the bacterial ABC2-type transporter signature and to ion transporters of H. pylori. Northern blot analysis detected an approximately 2.4-kb transcript at variable levels in all tissues tested. The highest expression was observed in heart, followed by brain and kidney; the lowest expression was observed in placenta.UNC93B1 is to deliver the nucleotide-sensing receptors TLR7 and TLR9 from the endoplasmic reticulum (ER) to the endolysosomes.