The subunits MECL-1 and LMP2 are mutually required for incorporation into the 20S proteasome
AUTOR(ES)
Groettrup, Marcus
FONTE
The National Academy of Sciences of the USA
RESUMO
Processing of antigens for presentation by major histocompatibility complex (MHC) class I molecules requires the activity of the proteasome. The 20S proteasome complex is composed of 14 different subunits, 2 of which can be substituted by the interferon γ (IFN-γ)-inducible and MHC-encoded subunits LMP2 and LMP7 (low molecular mass poylpeptides 2 and 7). A third subunit, MECL-1, is inducible by IFN-γ but is encoded outside the MHC. Here we show by cotransfection experiments that the incorporation of MECL-1 into the 20S proteasome is directly dependent on the expression of LMP2 but independent of LMP7. Conversely, the uptake of LMP2 is strongly enhanced by MECL-1 expression. The expression of MECL-1 caused a replacement of the homologous subunit Z in the 20S proteasome complex. LMP2 is required for MECL-1 incorporation at the level of proteasome precursor formation that guarantees the concerted incorporation of two IFN-γ-inducible proteasome subunits encoded inside and outside the MHC. The obligatory coincorporation of MECL-1 and LMP2 is an important parameter for the interpretation of results obtained with LMP2-deficient cell lines and mice as well as for the design of experiments addressing the function of MECL-1 in antigen presentation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=22989Documentos Relacionados
- Cleavage motifs of the yeast 20S proteasome β subunits deduced from digests of enolase 1
- The 20S Proteasome of Streptomyces coelicolor
- Genetic evidence for selective degradation of RNA polymerase subunits by the 20S proteasome in Saccharomyces cerevisiae.
- Identification of the yeast 20S proteasome catalytic centers and subunit interactions required for active-site formation
- Subunit arrangement in the human 20S proteasome
