S-Space College of Medicine/School of Medicine (의과대학/대학원) Internal Medicine (내과학전공) Journal Papers (저널논문_내과학전공)
CD99 regulates the transport of MHC class I molecules from the Golgi complex to the cell surface
- Sohn, Hae Won; Shin, Young Kee; Lee, Im-Soon; Bae, Young Mee; Suh, Young Ho; Kim, Min Kyung; Kim, Tae Jin; Jung, Kyeong Cheon; Park, Weon Seo; Park, Chan-Sik; Chung, Doo Hyun; Ahn, Kwang Seog; Kim, In Sun; Ko, Young Hyeh; Bang, Yung Jue; Kim, Chul Woo; Park, Seong Hoe
- Issue Date
- Journal of Immunology, Vol.166 No.2, pp.787-794
- The down-regulation of surface expression of MHC class I molecules has recently been reported in the CD99-deficient lymphoblastoid B cell line displaying the characteristics of Hodgkin's and Reed-Sternberg phenotype. Here, we demonstrate that the reduction of MHC class I molecules on the cell surface is primarily due to a defect in the transport from the Golgi complex to the plasma membrane. Loss of CD99 did not affect the steady-state expression levels of mRNA and protein of MHC class I molecules. In addition, the assembly of MHC class I molecules and the transport from the endoplasmic reticulum to the cis-Golgi occurred normally in the CD99-deficient cells, and no difference was detected between the CD99-deficient and the control cells in the pattern and degree of endocytosis. Instead, the CD99-deficient cells displayed the delayed transport of newly synthesized MHC class I molecules to the plasma membrane, thus causing accumulation of the molecules within the cells. The accumulated MHC class I molecules in the CD99-deficient cells were colocalized with alpha -mannosidase II and gamma -adaptin in the Golgi compartment, These results suggest that CD99 may be associated with the post-Golgi trafficking machinery by regulating the transport to the plasma membrane rather than the endocytosis of surface MHC class I molecules, providing a novel mechanism of MHC class I downregulation for immune escape.
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