Limits...
The transmembrane adaptor protein TRIM regulates T cell receptor (TCR) expression and TCR-mediated signaling via an association with the TCR zeta chain.

Kirchgessner H, Dietrich J, Scherer J, Isomäki P, Korinek V, Hilgert I, Bruyns E, Leo A, Cope AP, Schraven B - J. Exp. Med. (2001)

Bottom Line: T cell receptor (TCR)-interacting molecule (TRIM) is a recently identified transmembrane adaptor protein, which is exclusively expressed in T cells.Here we demonstrate that in mature T cells, TRIM preferentially interacts with the TCR via the TCR-zeta chains and to a lesser extent via the CD3-straightepsilon/gamma heterodimer.Collectively, our data identify TRIM as a novel integral component of the TCR complex and suggest that one function of TRIM might be to modulate the strength of signals transduced through the TCR through regulation of TCR expression on the cell surface.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology, Ruprecht-Karls University Heidelberg, D-69120 Heidelberg, Germany.

ABSTRACT
T cell receptor (TCR)-interacting molecule (TRIM) is a recently identified transmembrane adaptor protein, which is exclusively expressed in T cells. Here we demonstrate that in mature T cells, TRIM preferentially interacts with the TCR via the TCR-zeta chains and to a lesser extent via the CD3-straightepsilon/gamma heterodimer. Transient or stable overexpression of TRIM in Jurkat T cells results in enhancement of TCR expression on the cell surface and elevated induction of Ca(2+) mobilization after T cell activation. TRIM-mediated upregulation of TCR expression results from inhibition of spontaneous TCR internalization and stabilization of TCR complexes on the cell surface. Collectively, our data identify TRIM as a novel integral component of the TCR complex and suggest that one function of TRIM might be to modulate the strength of signals transduced through the TCR through regulation of TCR expression on the cell surface.

Show MeSH
Characterization of Jurkat clones stably overexpressing TRIM. (A) and (B) CD3ε and TCR-α/β expression (A) and subcellular localization of ζ (B) in a representative stably transfected Jurkat T clone (pos.; clone 2D1) compared with a transfectant not expressing TRIM (neg.; clone 2C3). (C) Mean channels of CD3ζ expression in six vector transfectants and in six TRIM transfectants as determined by flow cytometry. (D) Enhanced TCR-mediated Ca2+ flux in Jurkat T cells stably expressing F-TRIM and the F-15.5 mutant.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2193385&req=5

Figure 7: Characterization of Jurkat clones stably overexpressing TRIM. (A) and (B) CD3ε and TCR-α/β expression (A) and subcellular localization of ζ (B) in a representative stably transfected Jurkat T clone (pos.; clone 2D1) compared with a transfectant not expressing TRIM (neg.; clone 2C3). (C) Mean channels of CD3ζ expression in six vector transfectants and in six TRIM transfectants as determined by flow cytometry. (D) Enhanced TCR-mediated Ca2+ flux in Jurkat T cells stably expressing F-TRIM and the F-15.5 mutant.

Mentions: The experiments described above were performed using transiently transfected Jurkat T cells. To exclude the possibility that upregulation of TCR expression after overexpression of F-TRIM could only be observed in transiently transfected Jurkat T cells, we established a series of transfectants stably overexpressing F-TRIM. Fig. 7 A demonstrates that a representative Jurkat clone overexpressing F-TRIM also expresses higher amounts of TCR and CD3ε on the cell surface than a vector transfectant. Confocal laser scan analysis further revealed that also in this cell line the majority of endogenous ζ is localized at the plasma membrane (Fig. 7 B). Identical results were obtained for six additional clones of each group. On average, TRIM transfectants expressed 1.6 times more TCRs on the cell surface compared with the vector transfectants (Fig. 7 C). However, it is important to note that after prolonged periods of cell culture, the transfectants downregulated TCR expression to a certain extent. The molecular basis of this counterregulation is not known at present.


The transmembrane adaptor protein TRIM regulates T cell receptor (TCR) expression and TCR-mediated signaling via an association with the TCR zeta chain.

Kirchgessner H, Dietrich J, Scherer J, Isomäki P, Korinek V, Hilgert I, Bruyns E, Leo A, Cope AP, Schraven B - J. Exp. Med. (2001)

Characterization of Jurkat clones stably overexpressing TRIM. (A) and (B) CD3ε and TCR-α/β expression (A) and subcellular localization of ζ (B) in a representative stably transfected Jurkat T clone (pos.; clone 2D1) compared with a transfectant not expressing TRIM (neg.; clone 2C3). (C) Mean channels of CD3ζ expression in six vector transfectants and in six TRIM transfectants as determined by flow cytometry. (D) Enhanced TCR-mediated Ca2+ flux in Jurkat T cells stably expressing F-TRIM and the F-15.5 mutant.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2193385&req=5

Figure 7: Characterization of Jurkat clones stably overexpressing TRIM. (A) and (B) CD3ε and TCR-α/β expression (A) and subcellular localization of ζ (B) in a representative stably transfected Jurkat T clone (pos.; clone 2D1) compared with a transfectant not expressing TRIM (neg.; clone 2C3). (C) Mean channels of CD3ζ expression in six vector transfectants and in six TRIM transfectants as determined by flow cytometry. (D) Enhanced TCR-mediated Ca2+ flux in Jurkat T cells stably expressing F-TRIM and the F-15.5 mutant.
Mentions: The experiments described above were performed using transiently transfected Jurkat T cells. To exclude the possibility that upregulation of TCR expression after overexpression of F-TRIM could only be observed in transiently transfected Jurkat T cells, we established a series of transfectants stably overexpressing F-TRIM. Fig. 7 A demonstrates that a representative Jurkat clone overexpressing F-TRIM also expresses higher amounts of TCR and CD3ε on the cell surface than a vector transfectant. Confocal laser scan analysis further revealed that also in this cell line the majority of endogenous ζ is localized at the plasma membrane (Fig. 7 B). Identical results were obtained for six additional clones of each group. On average, TRIM transfectants expressed 1.6 times more TCRs on the cell surface compared with the vector transfectants (Fig. 7 C). However, it is important to note that after prolonged periods of cell culture, the transfectants downregulated TCR expression to a certain extent. The molecular basis of this counterregulation is not known at present.

Bottom Line: T cell receptor (TCR)-interacting molecule (TRIM) is a recently identified transmembrane adaptor protein, which is exclusively expressed in T cells.Here we demonstrate that in mature T cells, TRIM preferentially interacts with the TCR via the TCR-zeta chains and to a lesser extent via the CD3-straightepsilon/gamma heterodimer.Collectively, our data identify TRIM as a novel integral component of the TCR complex and suggest that one function of TRIM might be to modulate the strength of signals transduced through the TCR through regulation of TCR expression on the cell surface.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology, Ruprecht-Karls University Heidelberg, D-69120 Heidelberg, Germany.

ABSTRACT
T cell receptor (TCR)-interacting molecule (TRIM) is a recently identified transmembrane adaptor protein, which is exclusively expressed in T cells. Here we demonstrate that in mature T cells, TRIM preferentially interacts with the TCR via the TCR-zeta chains and to a lesser extent via the CD3-straightepsilon/gamma heterodimer. Transient or stable overexpression of TRIM in Jurkat T cells results in enhancement of TCR expression on the cell surface and elevated induction of Ca(2+) mobilization after T cell activation. TRIM-mediated upregulation of TCR expression results from inhibition of spontaneous TCR internalization and stabilization of TCR complexes on the cell surface. Collectively, our data identify TRIM as a novel integral component of the TCR complex and suggest that one function of TRIM might be to modulate the strength of signals transduced through the TCR through regulation of TCR expression on the cell surface.

Show MeSH