scholarly journals An orderly inactivation of intracellular retention signals controls surface expression of the T cell antigen receptor

2005 ◽  
Vol 201 (4) ◽  
pp. 555-566 ◽  
Author(s):  
Pilar Delgado ◽  
Balbino Alarcón
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Cell Surface ◽  
Cell Receptor ◽  
Surface Expression ◽  
Membrane Receptors ◽  
Membrane Expression ◽  
Er Retention ◽  
Er Retention Signal ◽  
Retention Signal

Exit from the endoplasmic reticulum (ER) is an important checkpoint for proper assembly of multimeric plasma membrane receptors. The six subunits of the T cell receptor (TCR; TCRα, TCRβ, CD3γ, CD3δ, CD3ε, and CD3ζ) are each endowed with ER retention/retrieval signals, and regulation of its targeting to the plasma membrane is therefore especially intriguing. We have studied the importance of the distinct ER retention signals at different stages of TCR intracellular assembly. To this end, we have characterized first the presence of ER retention signals in CD3γ. Despite the presence of multiple ER retention signals in CD3γ, εγ dimers reach the cell surface when the single CD3ε ER retention signal is deleted. Furthermore, inclusion of this CD3ε mutant promoted plasma membrane expression of incomplete αβγε and αβδε complexes without CD3ζ. It therefore appears that the CD3ε ER retention signal is dominant and that it is only overridden upon the incorporation of CD3ζ. We propose that the stepwise assembly of the TCR complex guarantees that all assembly intermediates have at least one functional ER retention signal and that only a full signaling-competent TCR complex is expressed on the cell surface.

Protein Phosphatase 2A Isotypes Regulate Cell Surface Expression of the T Cell Receptor

2001 ◽  
Vol 18 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Jens Peter H. Lauritsen ◽  
Charlotte Menné ◽  
Jesper Kastrup ◽  
Jes Dietrich ◽  
Carsten Geisler
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Receptor ◽  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Cell Receptor ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Phosphatase 2A

scholarly journals Regulating the retention of T-cell receptor alpha chain variants within the endoplasmic reticulum: Ca(2+)-dependent association with BiP.

1991 ◽  
Vol 114 (2) ◽  
pp. 189-205 ◽  
Author(s):  
C K Suzuki ◽  
J S Bonifacino ◽  
A Y Lin ◽  
M M Davis ◽  
R D Klausner
Keyword(s):  
T Cell ◽  
Cell Receptor ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Ionophore A23187 ◽  
Receptor Alpha ◽  
Alpha Chain ◽  
Er Retention ◽  
Receptor Alpha Chain

Immunoglobulin heavy chain binding protein (BiP, GRP 78) coprecipitates with soluble and membrane-associated variants of the T-cell antigen receptor alpha chain (TCR-alpha) which are stably retained within the ER. Chelation of Ca2+ during solubilization of cells leads to the dissociation of BiP from the TCR-alpha variants, which is dependent upon the availability of Mg2+ and hydrolyzable ATP; this suggests that Ca2+ levels can serve to modulate the association/dissociation of these proteins with BiP. In vivo treatment of cells expressing either the soluble or membrane-anchored TCR-alpha variants with the Ca2+ ionophore, A23187, or an inhibitor of an ER Ca(2+)-ATPase, thapsigargin, or the membrane-permeant Ca2+ chelator BAPTA-AM, results in the redistribution of these proteins out of the ER and their subsequent secretion or cell surface expression. Under the same assay conditions, no movement of BiP out of the ER is observed. Taken together, these observations indicate that decreased Ca2+ levels result in the dissociation of a protein bound to BiP, leading to its release from ER retention. These data suggest that the intracellular fate of newly synthesized proteins stably associated with BiP can be regulated by Ca2+ levels in the ER.

Engagement of the CD4 molecule influences cell surface expression of the T-cell receptor on thymocytes

Nature ◽  
1988 ◽  
Vol 336 (6194) ◽  
pp. 76-79 ◽  
Author(s):  
Susan A. McCarthy ◽  
Ada M. Kruisbeek ◽  
Ingeborg K. Uppenkamp ◽  
Susan O. Sharrow ◽  
Alfred Singer
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Surface Expression ◽  
Cell Surface Expression

scholarly journals Utilizing TAPBPR to promote exogenous peptide loading onto cell surface MHC I molecules

2018 ◽  
Vol 115 (40) ◽  
pp. E9353-E9361 ◽  
Author(s):  
F. Tudor Ilca ◽  
Andreas Neerincx ◽  
Mark R. Wills ◽  
Maike de la Roche ◽  
Louise H. Boyle
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Cell Surface ◽  
Cell Receptor ◽  
Target Cells ◽  
Intact Cells ◽  
Mhc I ◽  
Immunogenic Peptides ◽  
Presentation Pathway ◽  
Peptide Exchange

The repertoire of peptides displayed at the cell surface by MHC I molecules is shaped by two intracellular peptide editors, tapasin and TAPBPR. While cell-free assays have proven extremely useful in identifying the function of both of these proteins, here we explored whether a more physiological system could be developed to assess TAPBPR-mediated peptide editing on MHC I. We reveal that membrane-associated TAPBPR targeted to the plasma membrane retains its ability to function as a peptide editor and efficiently catalyzes peptide exchange on surface-expressed MHC I molecules. Additionally, we show that soluble TAPBPR, consisting of the luminal domain alone, added to intact cells, also functions as an effective peptide editor on surface MHC I molecules. Thus, we have established two systems in which TAPBPR-mediated peptide exchange on MHC class I can be interrogated. Furthermore, we could use both plasma membrane-targeted and exogenous soluble TAPBPR to display immunogenic peptides on surface MHC I molecules and consequently induce T cell receptor engagement, IFN-γ secretion, and T cell-mediated killing of target cells. Thus, we have developed an efficient way to by-pass the natural antigen presentation pathway of cells and load immunogenic peptides of choice onto cells. Our findings highlight a potential therapeutic use for TAPBPR in increasing the immunogenicity of tumors in the future.

scholarly journals SAT-LB137 Rescue of Misfolded G-Protein Coupled Estrogen Receptor, GPER, from the Endoplasmic Reticulum via Natural and Synthetic Estrogens

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Milad Rouhimoghadam ◽  
Jing Dong ◽  
Peter Thomas ◽  
Edward Joseph Filardo
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Cell Surface ◽  
G Protein ◽  
Surface Expression ◽  
Membrane Expression ◽  
Plasma Membrane Expression ◽  
17Β Estradiol ◽  
G Protein Coupled

Abstract GPER bears structural and functional characteristics shared by members of the G-protein coupled receptor (GPCR) superfamily, the largest class of cell surface receptors, with more than 800 members encoded in the human genome. GPER is localized predominately in intracellular membranes, in many but not all cell types, and its surface expression is modulated by steroid hormones and during tissue homeostasis. An intracellular staining pattern is not unique among GPCRs, which deploy a diverse array of posttranslational regulatory mechanisms to determine cell surface expression, effectively regulating cognate ligand binding and activity. Here, we show nascent GPER undergoes strict quality control via endoplasmic reticulum associated degradation (ERAD) requiring direct poly-ubiquitinylation of GPER and valosin-containing protein VCP/p97-mediated segregation of misfolded proteins from the ER membrane to the cytoplasm for delivery to the 26S proteasome. Specifically, we find that inhibition of p97 using the pharmacological compound, CB-5083, or by doxycycline-inducible p97 shRNA results in the accumulation of immature glycosylated GPER in the ER. Inhibition of proteasome function facilitates anterograde trafficking with the transport of nonfunctional GPER to the plasma membrane as indicated by no increase in specific estrogen binding using 3H-17β-estradiol in a radioreceptor assay. The forward trafficking of misfolded GPER requires transit through the Golgi as treatment with brefeldin A (BFA) prevents GPER plasma membrane expression. Substitution of all three lysines (K333, K342, and K357) encoded in the cytoplasmic tail of GPER with arginines blunts its polyubiquitinylation and allows GPER to evade degradation by quality control but does not result in increased plasma membrane expression suggesting that additional structural motifs encoded within GPER control its anterograde trafficking. In contrast, functional GPER is recovered at the plasma membrane of human SKBR3 breast cancer cells treated with either 17β-estradiol or the GPER selective antagonist, G15, in the presence of cycloheximide resulting in increased surface GPER. Thus, our findings suggest that estrogens, both natural and synthetic, can function as pharmacochaperones capable of promoting the correct folding of GPER and enhanced expression of functional GPER at the plasma membrane.

scholarly journals Allelic Exclusion in pTα-deficient Mice: No Evidence for Cell Surface Expression of Two T Cell Receptor (TCR)-β Chains, but Less Efficient Inhibition of Endogeneous Vβ→ (D)Jβ Rearrangements in the Presence of a Functional TCR-β Transgene

1997 ◽  
Vol 186 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Anna Krotkova ◽  
Harald von Boehmer ◽  
Hans Jörg Fehling
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Allelic Exclusion ◽  
Thymocyte Development ◽  
Β Chain ◽  
Deficient Mice

Although individual T lymphocytes have the potential to generate two distinct T cell receptor (TCR)-β chains, they usually express only one allele, a phenomenon termed allelic exclusion. Expression of a functional TCR-β chain during early T cell development leads to the formation of a pre-T cell receptor (pre-TCR) complex and, at the same developmental stage, arrest of further TCR-β rearrangements, suggesting a role of the pre-TCR in mediating allelic exclusion. To investigate the potential link between pre-TCR formation and inhibition of further TCR-β rearrangements, we have studied the efficiency of allelic exclusion in mice lacking the pre-TCR-α (pTα) chain, a core component of the pre-TCR. Staining of CD3+ thymocytes and lymph node cells with antibodies specific for Vβ6 or Vβ8 and a pool of antibodies specific for most other Vβ elements, did not reveal any violation of allelic exclusion at the level of cell surface expression. This was also true for pTα-deficient mice expressing a functionally rearranged TCR-β transgene. Interestingly, although the transgenic TCR-β chain significantly influenced thymocyte development even in the absence of pTα, it was not able to inhibit fully endogeneous TCR-β rearrangements either in total thymocytes or in sorted CD25+ pre-T cells of pTα−/− mice, clearly indicating an involvement of the pre-TCR in allelic exclusion.

scholarly journals Surface expression of only gamma delta and/or alpha beta T cell receptor heterodimers by cells with four (alpha, beta, gamma, delta) functional receptor chains.

1988 ◽  
Vol 168 (3) ◽  
pp. 1003-1020 ◽  
Author(s):  
T Saito ◽  
F Hochstenbach ◽  
S Marusic-Galesic ◽  
A M Kruisbeek ◽  
M Brenner ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Surface Expression ◽  
Gamma Delta ◽  
Stringent Control ◽  
Repertoire Diversity ◽  
Alpha Beta ◽  
Functional Receptor

Surface expression of TCR dimers by cells synthesizing three or four distinct types of receptor chains was analyzed. Cells containing intact gamma, alpha, and beta chains had only gamma delta dimers on the cell surface. In human PEER cells, addition of a functional alpha chain led to the loss of gamma delta dimer expression and expression of only alpha beta dimers. This result was not due to transcriptional down-regulation of the gamma or delta loci. In murine cells expressing all four chains, both gamma delta and alpha beta dimers could be demonstrated on a single cell. No other chain combinations (alpha gamma, alpha delta, beta gamma, or beta delta) were detected. Thus, there is stringent control of assembly and/or transport of TCR heterodimers, such that functional receptors consist only of alpha beta and gamma delta pairs, and no additional repertoire diversity is generated by cross pairing.

Efficiency of T-cell receptor expression in dual-specific T cells is controlled by the intrinsic qualities of the TCR chains within the TCR-CD3 complex

Blood ◽  
2006 ◽  
Vol 109 (1) ◽  
pp. 235-243 ◽  
Author(s):  
Mirjam H. M. Heemskerk ◽  
Renate S. Hagedoorn ◽  
Menno A. W. G. van der Hoorn ◽  
Lars T. van der Veken ◽  
Manja Hoogeboom ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Viral Infections ◽  
Cell Receptor ◽  
Surface Expression ◽  
Receptor Expression ◽  
Leukemic Cells ◽  
Cell Surface Expression ◽  
Cell Immunity

Abstract Genetic engineering of T lymphocytes is an attractive strategy to specifically redirect T-cell immunity toward viral infections and malignancies. We previously demonstrated redirected antileukemic reactivity of cytomegalovirus (CMV)–specific T cells by transfer of minor histocompatibility antigen HA-2–specific T-cell receptors (TCRs). HA-2–TCR-transferred CMV-specific T cells were potent effectors against HA-2–expressing leukemic cells, as well as CMV-expressing cells. Functional activity of these T cells correlated with TCR cell-surface expression. In the present study we analyzed which properties of transferred and endogenous TCRs are crucial for efficient cell-surface expression. We demonstrate that expression of the introduced TCR is not a random process but is determined by characteristics of both the introduced and the endogenously expressed TCR. The efficiency of TCR cell-surface expression is controlled by the intrinsic quality of the TCR complex. In addition, we demonstrate that chimeric TCRs can be formed and that efficiency of TCR expression is independent of whether TCRs are retrovirally introduced or naturally expressed. In conclusion, introduced, endogenous, and chimeric TCRs compete for cell-surface expression in favor of the TCR-CD3 complex with best-pairing properties.

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