Differential CD74 (major histocompatibility complex Class II invariant chain) expression in mouse and human intestinal adenomas

2009 ◽  
Vol 45 (9) ◽  
pp. 1654-1663 ◽  
Author(s):  
R.J. Cuthbert ◽  
J.M. Wilson ◽  
N. Scott ◽  
P.L. Coletta ◽  
M.A. Hull
Keyword(s):  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Invariant Chain ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

scholarly journals Related Leucine-based Cytoplasmic Targeting Signals in Invariant Chain and Major Histocompatibility Complex Class II Molecules Control Endocytic Presentation of Distinct Determinants in a Single Protein

1997 ◽  
Vol 185 (3) ◽  
pp. 429-438 ◽  
Author(s):  
Guangming Zhong ◽  
Paola Romagnoli ◽  
Ronald N. Germain
Keyword(s):  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Cytoplasmic Tail ◽  
Class Ii ◽  
Endocytic Pathway ◽  
Invariant Chain ◽  
Antigenic Peptides ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

Leucine-based signals in the cytoplasmic tail of invariant chain (Ii) control targeting of newly synthesized major histocompatibility complex class II molecules to the endocytic pathway for acquisition of antigenic peptides. Some protein determinants, however, do not require Ii for effective class II presentation, although endocytic processing is still necessary. Here we demonstrate that a dileucine-based signal in the cytoplasmic tail of the class II β chain is critical for this Ii-independent presentation. Elimination or mutation of this signal reduces the rate of re-entry of mature surface class II molecules into the endocytic pathway. Antigen presentation controlled by this signal does not require newly synthesized class II molecules and appears to involve determinants requiring only limited proteolysis for exposure, whereas the opposite is true for Ii-dependent determinants. This demonstrates that related leucine-based trafficking signals in Ii and class II control the functional presentation of protein determinants with distinct processing requirements, suggesting that the peptide binding sites of newly synthesized versus mature class II molecules are made available for antigen binding in distinct endocytic compartments under the control of these homologous cytoplasmic signals. This permits capture of protein fragments produced optimally under distinct conditions of pH and proteolytic activity.

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