Altered structure of HLA class I heavy chains associated with mouse beta-2 microglobulin

1985 ◽  
Vol 21 (4) ◽  
pp. 321-331 ◽  
Author(s):  
Pierre Ferrie ◽  
Juan C. Fontecilla-Camps ◽  
Danielle Bucchini ◽  
Dani�le H. Caillol ◽  
Bertrand R. Jordan ◽  
...  
Keyword(s):  
Hla Class I ◽  
Class I ◽  
Heavy Chains ◽  
Beta 2 ◽  
Beta 2 Microglobulin

scholarly journals Activated human T lymphocytes express MHC class I heavy chains not associated with beta 2-microglobulin.

1990 ◽  
Vol 171 (5) ◽  
pp. 1431-1442 ◽  
Author(s):  
E Schnabl ◽  
H Stockinger ◽  
O Majdic ◽  
H Gaugitsch ◽  
I J Lindley ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Mhc Class I ◽  
Hla Class I ◽  
Class I ◽  
Heavy Chains ◽  
Human T Lymphocytes ◽  
Beta 2 ◽  
Beta 2 Microglobulin ◽  
Mhc Class I Molecules

We present here the molecular characterization of a new activation-induced surface structure on human T lymphocytes, termed LA45, with high homology (93% at protein level) to MHC class I molecules. Antigen modulation and sequential immunoprecipitation experiments revealed that LA45 and HLA class I proteins do not crossreact with the corresponding antibodies. Furthermore, LA45 is not associated with beta 2-m. On the other hand, we could show that the separation of HLA-A,B,C and beta 2m molecules, induced by SDS-denaturation, leads to a conformational change in the heavy chain in such a way that it becomes reactive with LA45. The 90/45 kD LA45 proteins thus appear to be non-beta 2m-associated MHC class I alpha chains that are selectively expressed by activated but not by resting human T lymphocytes.

scholarly journals Functionally conformed free class I heavy chains exist on the surface of beta 2 microglobulin negative cells.

1992 ◽  
Vol 176 (3) ◽  
pp. 829-834 ◽  
Author(s):  
M Bix ◽  
D Raulet
Keyword(s):  
Functional Class ◽  
Class I ◽  
Target Cells ◽  
Antigenic Peptides ◽  
Heavy Chains ◽  
Domain Specific ◽  
Histocompatibility Complex ◽  
Beta 2 ◽  
Beta 2 Microglobulin ◽  
Serum Free Conditions

Cytotoxic T lymphocytes (CTL) can recognize antigenic peptides bound in a groove formed by the alpha 1 and alpha 2 domains of the heterodimeric major histocompatibility complex class I molecule. Proper assembly, transport, and stability of functional class I molecules is thought to require beta 2 microglobulin (beta 2m), the light chain of the class I heterodimer. We show here that the requirement for beta 2m is not absolute. beta 2m- cells can be stained by the Db alpha 1 domain-specific B22-249.1 monoclonal antibody, which detects a conformation-dependent epitope. Furthermore, beta 2m- Con A blast target cells can be lysed by alloreactive CTL, even in serum-free conditions. Contrary to previous reports, the expression of low levels of conformed Db heavy (H) chains is a property to both normal and transformed beta 2m- cells. Finally, we present evidence that a subset of properly conformed H chains, free of beta 2m, may have almost equal representation on beta 2m+ and beta 2m- cells.

scholarly journals Participation of a novel 88-kD protein in the biogenesis of murine class I histocompatibility molecules.

1991 ◽  
Vol 112 (6) ◽  
pp. 1099-1115 ◽  
Author(s):  
E Degen ◽  
D B Williams
Keyword(s):  
Heavy Chain ◽  
Gel Permeation Chromatography ◽  
Class I ◽  
Specific Class ◽  
Antigenic Peptides ◽  
Heavy Chains ◽  
Golgi Transport ◽  
Beta 2 ◽  
Beta 2 Microglobulin ◽  
Rate Limiting

Chemical cross-linking and gel permeation chromatography were used to examine early events in the biogenesis of class I histocompatibility molecules. We show that newly synthesized class I heavy chains associate rapidly and quantitatively with an 88-kD protein in three murine tumor cell lines. This protein (p88) does not appear to possess Asn-linked glycans and it is not the abundant ER protein, GRP94. The class I-p88 complex exists transiently (t1/2 = 20-45 min depending on the specific class I heavy chain) and several lines of evidence suggest that p88 dissociates from the complex while still in the ER. Dissociation is not triggered upon binding of beta 2-microglobulin to the heavy chain (t1/2 = 2-5 min). However, the rate of dissociation does correlate with the characteristic rate of ER to Golgi transport for the particular class I molecule studied. Consequently, dissociation of p88 may be rate limiting for ER to Golgi transport. Class I molecules bind antigenic peptides, apparently in the ER, for subsequent presentation to cytotoxic T lymphocytes at the cell surface. p88 could promote peptide binding or it may retain class I molecules in the ER during formation of the ternary complex of heavy chain, beta 2-microglobulin, and peptide.

scholarly journals Translocation of peptides through microsomal membranes is a rapid process and promotes assembly of HLA-B27 heavy chain and beta 2-microglobulin translated in vitro.

1991 ◽  
Vol 115 (4) ◽  
pp. 959-970 ◽  
Author(s):  
F Lévy ◽  
R Larsson ◽  
S Kvist
Keyword(s):  
Mhc Class I ◽  
Heavy Chain ◽  
Peptide Binding ◽  
Class I ◽  
Hla B27 ◽  
Heavy Chains ◽  
Microsomal Membranes ◽  
Beta 2 ◽  
Beta 2 Microglobulin

We have translated major histocompatibility complex (MHC) class I heavy chains and human beta 2-microglobulin in vitro in the presence of microsomal membranes and a peptide from the nucleoprotein of influenza A. This peptide stimulates assembly of HLA-B27 heavy chain and beta 2-microglobulin about fivefold. By modifying this peptide to contain biotin at its amino terminus, we could precipitate HLA-B27 heavy chains with immobilized streptavidin, thereby directly demonstrating class I heavy chain-peptide association under close to physiological conditions. The biotin-modified peptide stimulates assembly to the same extent as the unmodified peptide. Both peptides bind to the same site on the HLA-B27 molecule. Immediately after synthesis of the HLA-B27 heavy chain has been completed, it assembles with beta 2-microglobulin and peptide. These interactions occur in the lumen of the microsomes (endoplasmic reticulum), demonstrating that the peptide must cross the microsomal membrane in order to promote assembly. The transfer of peptide across the microsomal membrane is a rapid process, as peptide binding to heavy chain-beta 2-microglobulin complexes is observed in less than 1 min after addition of peptide. By using microsomes deficient of beta 2-microglobulin (from Daudi cells), we find a strict requirement of beta 2-microglobulin for detection of peptide interaction with the MHC class I heavy chain. Furthermore, we show that heavy chain interaction with beta 2-microglobulin is likely to precede peptide binding. Biotin-modified peptides are likely to become a valuable tool in studying MHC antigen interaction and assembly.

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.

scholarly journals Beta 2-microglobulin induces intracellular transport of human class I transplantation antigen heavy chains in Xenopus laevis oocytes.

1984 ◽  
Vol 99 (1) ◽  
pp. 226-232 ◽  
Author(s):  
L Severinsson ◽  
P A Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Xenopus Laevis ◽  
Intracellular Transport ◽  
Class I ◽  
Transplantation Antigen ◽  
Xenopus Laevis Oocytes ◽  
Human Class ◽  
Heavy Chains ◽  
Beta 2 ◽  
Beta 2 Microglobulin

Human class I transplantation antigens are cell-surface-expressed molecules composed of one glycosylated, membrane-integrated heavy chain and one nonglycosylated, water-soluble subunit, beta 2-microglobulin (beta 2m). We have examined the intracellular transport of the two subunits by microinjecting mRNA into Xenopus laevis oocytes. Beta 2m, translated in oocytes, was transported and secreted into the medium in the absence of heavy chains whereas heavy chains were retained in the endoplasmic reticulum if not cotranslated with beta 2m. In the presence of beta 2m, heavy chains resisted digestion by endoglycosidase H (Endo H), suggesting that beta 2m promotes the transport of heavy chains from endoplasmic reticulum to the Golgi compartment. Pulse-chase experiments confirmed this notion. The possibility that heavy chains aggregate irreversibly when synthesized in the absence of beta 2m was ruled out and it is demonstrated that performed heavy chains will become transported once beta 2m is available. It is suggested that intracellular transport is controlled by structural features that are part of the transported polypeptide. If so, beta 2m but not heavy chains may possess such features.

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