Kinetics and Thermodynamics of β2-Microglobulin Binding to the α3 Domain of Major Histocompatibility Complex Class I Heavy Chain†

Biochemistry ◽  
2001 ◽  
Vol 40 (17) ◽  
pp. 5233-5242 ◽  
Author(s):  
Andrea M. Hebert ◽  
Jason Strohmaier ◽  
Mary C. Whitman ◽  
Trina Chen ◽  
Elena Gubina ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Heavy Chain ◽  
Class I ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Kinetics And Thermodynamics ◽  
Β2 Microglobulin ◽  
Histocompatibility Complex

scholarly journals Efficient dissociation of the p88 chaperone from major histocompatibility complex class I molecules requires both beta 2-microglobulin and peptide.

1992 ◽  
Vol 175 (6) ◽  
pp. 1653-1661 ◽  
Author(s):  
E Degen ◽  
M F Cohen-Doyle ◽  
D B Williams
Keyword(s):  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Heavy Chain ◽  
Class I ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Heavy Chains ◽  
Histocompatibility Complex ◽  
Beta 2 ◽  
Beta 2 Microglobulin

Previously, we showed that an 88-kD protein (p88) associates rapidly and quantitatively with newly synthesized murine major histocompatibility complex class I molecules within the endoplasmic reticulum (ER). This interaction is transient and dissociation of p88 appears to be rate limiting for transport of class I molecules from the ER to the Golgi apparatus. In this report, we examine the relationship between p88 interaction and assembly of the ternary complex of class I heavy chain beta 2-microglobulin (beta 2m), and peptide ligand. In both murine and human beta 2m-deficient cells, in which little or no transport of class I heavy chains is observed, p88 remained associated with intracellular heavy chains throughout their lifetime. In murine RMA-S cells, which are apparently defective in accumulating peptide ligands for class I within the ER, prolonged association of p88 with "empty" heavy chain-beta 2m heterodimers was also observed. However, p88 dissociated slowly in parallel with the slow rate of ER to Golgi transport of empty class I molecules in these cells. The close correlation between p88 association and impaired class I transport suggests that p88 functions to retain incompletely assembled class I molecules in the ER. We propose that conformational changes in class I heavy chains induced by the binding of both beta 2m and peptide are required for efficient p88 dissociation and subsequent class I transport.

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