Intracellular trafficking pathway of newly synthesized CD1b molecules.
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.
Briken
V
V
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Jackman
R M
RM
Dasgupta
S
S
Hoening
S
S
Porcelli
S A
SA
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
D033963:Adaptor Protein Complex 3; D018949:Antigens, CD1; C419394:CD1b antigen; D002966:Clathrin; D004268:DNA-Binding Proteins; D014157:Transcription Factors