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A novel lysosome-associated membrane glycoprotein, DC-LAMP, induced upon DC maturation, is transiently expressed in
B de Saint-Vis1, J Vincent, S Vandenabeele
1Schering-Plough Laboratory for Immunological Research, Dardilly, France.
Abstract:
We have identified a novel lysosome-associated membrane glycoprotein localized on chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is present only in lymphoid organs and DC. A specific MAb detects the protein exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases progressively during in vitro DC differentiation, but sharply upon activation with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II compartment immediately before the translocation of MHC class II molecules to the cell surface, after which it concentrates into perinuclear lysosomes. This suggests that DC-LAMP might change the lysosome function after the transfer of peptide-MHC class II molecules to the surface of DC.
Insights
We discovered DC-LAMP, a novel protein in dendritic cells (DCs), that is linked to lysosome function. Its expression increases during DC activation, suggesting a role in immune responses.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Dendritic cells (DCs) are crucial for initiating immune responses.
- Lysosome-associated membrane glycoproteins play roles in cellular processes.
- The specific function of DC-LAMP (dendritic cell lysosomal-associated membrane protein) in DCs remains largely uncharacterized.
Purpose of the Study:
- To identify and characterize a novel lysosome-associated membrane glycoprotein in dendritic cells.
- To investigate the expression pattern and cellular localization of DC-LAMP.
- To explore the potential role of DC-LAMP in DC maturation and function.
Main Methods:
- Identification of DC-LAMP via homology to CD68 and chromosomal localization.
- Analysis of DC-LAMP mRNA expression in various tissues and cell types.
- Detection of DC-LAMP protein using a specific monoclonal antibody (MAb).
- In vitro studies of DC-LAMP expression during dendritic cell differentiation and activation.
- Confocal microscopy to determine subcellular localization.
- Analysis of DC-LAMP co-localization with MHC class II molecules.
Main Results:
- A novel lysosome-associated membrane glycoprotein, DC-LAMP, was identified on chromosome 3q26.3-q27, homologous to CD68.
- DC-LAMP mRNA is specifically expressed in lymphoid organs and dendritic cells.
- The protein is exclusively detected in interdigitating dendritic cells.
- DC-LAMP expression increases during in vitro DC differentiation and significantly upon activation with LPS, TNFalpha, or CD40L.
- Confocal microscopy confirmed DC-LAMP's lysosomal localization.
- DC-LAMP was observed in the MHC class II compartment before MHC class II molecule surface translocation and subsequently concentrated in perinuclear lysosomes.
Conclusions:
- DC-LAMP is a novel dendritic cell-specific lysosome-associated membrane glycoprotein.
- Its expression pattern and dynamic localization suggest a role in dendritic cell maturation and immune response modulation.
- DC-LAMP may influence lysosome function following the surface expression of peptide-MHC class II complexes.