T-cell surface glycoprotein CD1e, soluble binds diacetylated lipids, including phosphatidyl inositides and diacylated sulfoglycolipids, and is required for the presentation of glycolipid antigens on the cell surface. The membrane-associated form is not active. Heterodimer with B2M (beta-2-microglobulin). The association with B2M appears to be facilitated by the presence of the propeptide. Predominantly localized in the trans-Golgi network in immature dendritic cells, and as a cleaved, soluble protein in the lysosome lumen of mature dendritic cells. Expressed on cortical thymocytes, dendritic cells, Langerhans cells, on certain T-cell leukemias, and in various other tissues. Mono-ubiquitinated. Proteolytically cleaved in late endosomes to yield a soluble form. Six alleles of CD1E are known. CD1E*01 has His-102/Gln-106/Ser-149/Arg-164/Leu-194, CD1E*02 has His-102/Arg-106/Ser-149/Arg-164/Leu-194, CD1E*03 (9L) has His-102/Gln-106/Ser-149/Trp-164/Leu-194, CD1E*04 (15L) has His-102/Gln-106/Ser-149/Arg-164/Pro-194, CD1E*05 has Arg-102/Arg-106/Ser-149/Arg-164/Leu-194 and CD1E*06 has His-102/Arg-106/Asn-149/Arg-164/Leu-194 (PubMed:12144626, PubMed:11019917, PubMed:18325888). The sequence shown is that of allele CD1E*01.