First Author | Pierre P | Year | 2000 |
Journal | J Exp Med | Volume | 191 |
Issue | 6 | Pages | 1057-62 |
PubMed ID | 10727467 | Mgi Jnum | J:61107 |
Mgi Id | MGI:1354453 | Doi | 10.1084/jem.191.6.1057 |
Citation | Pierre P, et al. (2000) Invariant chain controls H2-M proteolysis in mouse splenocytes and dendritic cells. J Exp Med 191(6):1057-62 |
abstractText | The association of invariant (Ii) chain with major histocompatibility complex (MHC) class II dimers is required for proper antigen presentation to T cells by antigen-presenting cells. Mice lacking Ii chain have severe abnormalities in class II transport, T cell selection, and B cell maturation. We demonstrate here that H2-M, which is required for efficient class II antigenic peptide loading, is unexpectedly downregulated in splenocytes and mature dendritic cells (DCs) from Ii(-/-) mice. Downregulation reflects an increased rate of degradation in Ii(-/-) cells. Degradation apparently occurs within lysosomes, as it is prevented by cysteine protease inhibitors such as E64, but not by the proteasome inhibitor lactacystin. Thus, Ii chain may act as a lysosomal protease inhibitor in B cells and DCs, with its deletion contributing indirectly to the loss of H2-M. |