Mutation of the Invariant Chain Transmembrane Region Inhibits Ii Degradation, Prolongs Association with MHC Class II, and Selectively Disrupts Antigen Presentation

2001 ◽  
Vol 209 (2) ◽  
pp. 97-108 ◽  
Author(s):  
Kenneth Frauwirth ◽  
Nilabh Shastri
Keyword(s):  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Invariant Chain ◽  
Transmembrane Region

scholarly journals Epitope-specific enhancement of antigen presentation by invariant chain.

1993 ◽  
Vol 178 (4) ◽  
pp. 1453-1458 ◽  
Author(s):  
F Momburg ◽  
S Fuchs ◽  
J Drexler ◽  
R Busch ◽  
M Post ◽  
...  
Keyword(s):  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Brefeldin A ◽  
Class Ii ◽  
Endocytic Pathway ◽  
Invariant Chain ◽  
Target Class ◽  
Egg White Lysozyme ◽  
Hen Egg White ◽  
Enhance Antigen Presentation

The MHC class II-associated invariant chain (Ii) is involved in the intracellular sorting of class II molecules to the endocytic pathway where peptides from processed exogenous antigens are bound, and thereby Ii is thought to enhance antigen presentation. Here we demonstrate that presentation of only one out of five epitopes of a given antigen is augmented by Ii. We have compared the presentation of five different epitopes derived from hen egg white lysozyme (HEL) to Ak-restricted T hybridomas by rat-2 fibroblasts transfected with A alpha k and A beta k (RKK) and RKK cells supertransfected with the mouse invariant chain (RKKI). Only the presentation of the HEL epitope 46-61 was enhanced whereas the presentation of the HEL epitopes 25-43, 34-45, 112-124, and 116-129 was unchanged or even slightly diminished in RKKI cells. The presentation of the epitopes 25-43 and 34-45 was virtually insensitive to the lysosomotropic reagent chloroquine. Brefeldin A (BFA), which inhibits protein egress from the endoplasmic reticulum, blocked the presentation of all epitopes tested in RKKI cells. In contrast, in Ii-negative RKK cells only the presentation of the epitope HEL(46-61) was inhibited by BFA and the presentation of the epitopes 25-43 and 34-45 was only slightly impaired. These findings suggest that Ii may target class II molecules to selected endosomal subcompartments involved in the processing of different peptides derived from an endocytosed antigen. As a result, the enhancement of the class II-restricted presentation in Ii expressing cells appears to be epitope specific rather than antigen specific.

Sorting of MHC class II molecules and the associated invariant chain (Ii) in polarized MDCK cells

1997 ◽  
Vol 110 (5) ◽  
pp. 597-609 ◽  
Author(s):  
A. Simonsen ◽  
E. Stang ◽  
B. Bremnes ◽  
M. Roe ◽  
K. Prydz ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Mdck Cells ◽  
Intracellular Localization ◽  
Cytoplasmic Tail ◽  
Class Ii ◽  
Invariant Chain ◽  
Basolateral Targeting ◽  
Mhc Class Ii Molecules

Epithelial cells have been found to express MHC class II molecules in vivo and are able to perform class II-restricted antigen presentation. The precise intracellular localization of these molecules in epithelial cells has been a matter of debate. We have analyzed the polarized targeting of human MHC class II molecules and the associated invariant chain (Ii) in stably transfected MDCK cells. The class II molecules are located at the basolateral surface and in intracellular vesicles, both when expressed alone or together with Ii. Ii is located in basolateral endosomes and can internalize through the basolateral plasma membrane domain. We show that the cytoplasmic tail of Ii contains information for basolateral targeting as it is sufficient to redirect the apical protein neuraminidase (NA) to the basolateral surface. We find that the two leucine-based motifs (LI and ML) in the cytoplasmic tail of Ii are individually sufficient for endosomal sorting and basolateral targeting of Ii in MDCK cells. In addition, basolateral sorting information is located within the 10 membrane-proximal residues of the Ii cytoplasmic tail. As several different signals mediate basolateral sorting of the class II/Ii complex, a polarized distribution of these molecules may be an essential feature of antigen presentation in epithelial cells.

scholarly journals Sorting signals in the MHC class II invariant chain cytoplasmic tail and transmembrane region determine trafficking to an endocytic processing compartment.

1994 ◽  
Vol 126 (2) ◽  
pp. 317-330 ◽  
Author(s):  
C G Odorizzi ◽  
I S Trowbridge ◽  
L Xue ◽  
C R Hopkins ◽  
C D Davis ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Mhc Class Ii ◽  
Cytoplasmic Tail ◽  
Class Ii ◽  
Endocytic Pathway ◽  
Invariant Chain ◽  
Transmembrane Region ◽  
Coated Pits ◽  
Endocytic Compartment ◽  
Sorting Signals

Targeting of MHC class II molecules to the endocytic compartment where they encounter processed antigen is determined by the invariant chain (Ii). By analysis of Ii-transferrin receptor (TR) chimera trafficking, we have identified sorting signals in the Ii cytoplasmic tail and transmembrane region that mediate this process. Two non-tyrosine-based sorting signals in the Ii cytoplasmic tail were identified that mediate localization to plasma membrane clathrin-coated pits and promote rapid endocytosis. Leu7 and Ile8 were required for the activity of the signal most distal to the cell membrane whereas Pro15 Met16 Leu17 were important for the membrane-proximal signal. The same or overlapping non-tyrosine-based sorting signals are essential for delivery of Ii-TR chimeras, either by an intracellular route or via the plasma membrane, to an endocytic compartment where they are rapidly degraded. The Ii transmembrane region is also required for efficient delivery to this endocytic processing compartment and contains a signal distinct from the Ii cytoplasmic tail. More than 80% of the Ii-TR chimera containing the Ii cytoplasmic tail and transmembrane region is delivered directly to the endocytic pathway by an intracellular route, implying that the Ii sorting signals are efficiently recognized by sorting machinery located in the trans-Golgi.

Maturation and antigen presentation function of dendritic cells lacking the MHC class II associated invariant chain

1997 ◽  
Vol 56 ◽  
pp. 121
Author(s):  
P. Rovere ◽  
V.S. Zimmermann ◽  
F. Forquet ◽  
J. Trucy ◽  
P. Ricciardi-Castagnoli ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Invariant Chain
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