TY - JOUR
T1 - Invariant chain made in Escherichia coli has an exposed N-terminal segment that blocks antigen binding to HLA-DR1 and a trimeric C-terminal segment that binds empty HLA-DR1
AU - Park, Seong Joon
AU - Sadeoh-Nasseri, Scheherazade
AU - Wiley, Don C.
PY - 1995/11/21
Y1 - 1995/11/21
N2 - Invariant chain (Ii), a membrane glycoprotein, binds class II major histocompatibility complex (MHC) glycoproteins, probably via its class II- associated Ii peptide (CLIP) segment, and escorts them toward antigen- containing endosomal compartments. We find that a soluble, trimeric ectodomain of Ii expressed and purified from Escherichia colt blocks peptide binding to soluble HLA-DR1. Proteolysis indicates that Ii contains two structural domains. The C-terminal two-thirds forms an α-helical domain that trimerizes and interacts with empty HLA-DR1 molecules, augmenting rather than blocking peptide binding. The N-terminal one-third, which inhibits peptide binding, is proteolytically susceptible over its entire length. In the trimer, the N-terminal domains act independently with each CLIP segment exposed and free to bind an MHC class II molecule, while the C-terminal domains act as a trimeric unit.
AB - Invariant chain (Ii), a membrane glycoprotein, binds class II major histocompatibility complex (MHC) glycoproteins, probably via its class II- associated Ii peptide (CLIP) segment, and escorts them toward antigen- containing endosomal compartments. We find that a soluble, trimeric ectodomain of Ii expressed and purified from Escherichia colt blocks peptide binding to soluble HLA-DR1. Proteolysis indicates that Ii contains two structural domains. The C-terminal two-thirds forms an α-helical domain that trimerizes and interacts with empty HLA-DR1 molecules, augmenting rather than blocking peptide binding. The N-terminal one-third, which inhibits peptide binding, is proteolytically susceptible over its entire length. In the trimer, the N-terminal domains act independently with each CLIP segment exposed and free to bind an MHC class II molecule, while the C-terminal domains act as a trimeric unit.
KW - antigen processing
KW - major histocompatibility complex class II
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U2 - 10.1073/pnas.92.24.11289
DO - 10.1073/pnas.92.24.11289
M3 - Article
C2 - 7479981
AN - SCOPUS:0028791680
SN - 0027-8424
VL - 92
SP - 11289
EP - 11293
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 24
ER -