title: Intracellular trafficking pathway of newly synthesized CD1b molecules.
abstract: The intracellular trafficking of major histocompatibility complex (MHC) class I and class II molecules has evolved to support their function in peptide antigen presentation optimally. We have analyzed the intracellular trafficking of newly synthesized human CD1b, a lipid antigen-presenting molecule, to understand how this relates to its antigen-presenting function. Nascent CD1b was transported rapidly to the cell surface after leaving the Golgi, and then entered the endocytic system by internalization via AP-2-dependent sorting at the plasma membrane. A second sorting event, possibly involving AP-3 complexes, led to prominent accumulation of CD1b in MHC class II compartments (MIICs). Functional studies demonstrated the importance of nascent CD1b for the efficient presentation of a foreign lipid antigen. Therefore, the intracellular trafficking of nascent CD1b via the cell surface to reach MIICs may allow the efficient sampling of lipid antigens present in endocytic compartments.
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: V
authors.initials: V
authors.lastname: Briken
authors.forename: R M
authors.initials: RM
authors.lastname: Jackman
authors.forename: S
authors.initials: S
authors.lastname: Dasgupta
authors.forename: S
authors.initials: S
authors.lastname: Hoening
authors.forename: S A
authors.initials: SA
authors.lastname: Porcelli
mesh_terms: D033963:Adaptor Protein Complex 3; D000595:Amino Acid Sequence; D018949:Antigens, CD1 / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004705:Endocytosis; D006056:Golgi Apparatus / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D033963:Adaptor Protein Complex 3; D018949:Antigens, CD1; C419394:CD1b antigen; D002966:Clathrin; D004268:DNA-Binding Proteins; D014157:Transcription Factors