Characterization of CD1e, a Third Type of CD1 Molecule Expressed in Dendritic Cells

doi:10.1074/jbc.M007082200

Characterization of CD1e, a Third Type of CD1 Molecule Expressed in Dendritic Cells*

From Equipe Propre INSERM 99-08 and^§Unité INSERM 311, Etablissement Français du Sang-Alsace, Strasbourg 67065, France and ^‡UMR CNRS 144, Institut Curie, Paris 75005, France

Abstract

Dendritic cells express several alternatively spliced CD1e mRNAs. These molecules encode proteins characterized by the presence of either one, two, or three α domains and either a 51- or 63-amino acid cytoplasmic domain. Moreover, mRNAs encoding isoforms lacking the transmembrane domain are observed. Several of these CD1e isoforms were expressed in transfected cells, and two of them, with three α domains, displayed a particular processing pathway. These latter isoforms slowly leave the endoplasmic reticulum due to the presence of atypical dilysine motifs in the cytoplasmic tail. These molecules are associated with the β₂-microglobulin and accumulate in late Golgi and late endosomal compartments. In the latter compartments, they are cleaved into soluble forms that appear to be stable. In dendritic cells, these isoforms are mainly located in the Golgi apparatus, and upon maturation they are redistributed to late endosomal compartments. This work demonstrates the existence of CD1e molecules. As compared with other CD1 molecules, CD1e displays fundamentally different properties and therefore may represent a third type of CD1 molecules.

Footnotes

↵* This work was supported by the Etablissement Français du Sang-Alsace, INSERM, and Association pour la Recherche sur le Cancer Grant 9411.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) to .
↵¶ To whom correspondence should be addressed. Tel.: 33 3 882 125 25; Fax: 33 3 882 125 44; E-mail: henri.delasalle@efs-alsace.fr.
Published, JBC Papers in Press, August 17, 2000, DOI 10.1074/jbc.M007082200
↵2 D. Hanau and J. Salamero, unpublished observations.
↵3 C. Angénieux, unpublished observations.
- Received August 4, 2000.
The American Society for Biochemistry and Molecular Biology, Inc.