scholarly journals The MHC class II   chain cytoplasmic tail overcomes the invariant chain p35-encoded endoplasmic reticulum retention signal

2003 ◽  
Vol 15 (10) ◽  
pp. 1249-1263 ◽  
Author(s):  
H. Khalil
Keyword(s):  
Endoplasmic Reticulum ◽  
Mhc Class Ii ◽  
Cytoplasmic Tail ◽  
Class Ii ◽  
Invariant Chain ◽  
Endoplasmic Reticulum Retention ◽  
Endoplasmic Reticulum Retention Signal ◽  
Retention Signal

scholarly journals Defective Human Ether-à-go-go-related Gene Trafficking Linked to an Endoplasmic Reticulum Retention Signal in the C Terminus

2002 ◽  
Vol 277 (30) ◽  
pp. 27442-27448 ◽  
Author(s):  
Sabina Kupershmidt ◽  
Tao Yang ◽  
Siprachanh Chanthaphaychith ◽  
Zhiqing Wang ◽  
Jeffrey A. Towbin ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Related Gene ◽  
Endoplasmic Reticulum Retention ◽  
C Terminus ◽  
Endoplasmic Reticulum Retention Signal ◽  
Retention Signal

scholarly journals The MHC class II-associated invariant chain contains two endosomal targeting signals within its cytoplasmic tail

1993 ◽  
Vol 106 (3) ◽  
pp. 831-846 ◽  
Author(s):  
J. Pieters ◽  
O. Bakke ◽  
B. Dobberstein
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Mhc Class Ii ◽  
Cytoplasmic Tail ◽  
Class Ii ◽  
Endocytic Pathway ◽  
Invariant Chain ◽  
Amino Acid Residues ◽  
Marker Proteins ◽  
Membrane Spanning

The oligomeric complex formed by major histocompatibility complex (MHC) class II alpha and beta chains and invariant chain (Ii) assembles in the endoplasmic reticulum and is then transported via the Golgi complex to compartments of the endocytic pathway. When Ii alone is expressed in CV1 cells it is sorted to endosomes. The Ii cytoplasmic tail has been found to be essential for targeting to these compartments. In order to characterize further the signals responsible for endosomal targeting, we have deleted various segments of the cytoplasmic tail. The Ii mutants were transiently expressed and the cellular location of the proteins was analyzed biochemically and morphologically. The cytoplasmic tail of Ii was found to contain two endosomal targeting sequences within its cytoplasmic tail; one targeting sequence was present within amino acid residues 12–29 and deletion of this segment revealed the presence of a second endosomal targeting sequence, located within the first 11 amino acid residues. The presence of a leucine-isoleucine pair at positions 7 and 8 within this sequence was found to be essential for endosomal targeting. In addition, the presence of this L-I motif lead to accumulation of Ii molecules in large endosomal vacuoles containing lysosomal marker proteins. Both wild type Ii and Ii mutant molecules containing only one endosomal targeting sequence were rapidly internalized from the plasma membrane. When the Ii cytoplasmic tail was fused to the membrane-spanning region of neuraminidase, a resident plasma membrane protein, the resulting chimera (INA) was found in endocytic compartments containing lysosomal marker proteins. Thus the cytoplasmic tail of Ii is sufficient for targeting to the endocytic/lysosomal pathway.

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.

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