PDBsum entry 2k4f

Immune system, signaling protein

PDB id: 2k4f

Contents

Protein chain

57 a.a. *

* Residue conservation analysis

PDB id:

2k4f

Name:

Immune system, signaling protein

Title:

Mouse cd3epsilon cytoplasmic tail

Structure:

T-cell surface glycoprotein cd3 epsilon chain. Chain: a. Fragment: cytoplasmic domain. Synonym: t-cell surface antigen t3/leu-4 epsilon chain. Engineered: yes

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: cd3e. Expressed in: escherichia coli.

NMR struc:

20 models

Authors:

C.Xu,M.E.Call,C.D.Schwieters,J.R.Schnell,E.E.Gagnon, K.W.Wucherpfennig,J.J.Chou

Key ref:

C.Xu et al. (2008). Regulation of T cell receptor activation by dynamic membrane binding of the CD3epsilon cytoplasmic tyrosine-based motif. Cell, 135, 702-713. PubMed id: 19013279 DOI: 10.1016/j.cell.2008.09.044

Date:

07-Jun-08 Release date: 02-Dec-08

Protein chain

P22646  (CD3E_MOUSE) -  T-cell surface glycoprotein CD3 epsilon chain from Mus musculus

Seq: 189 a.a.

Struc: 57 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/j.cell.2008.09.044

Cell 135:702-713 (2008)

PubMed id: 19013279

Regulation of T cell receptor activation by dynamic membrane binding of the CD3epsilon cytoplasmic tyrosine-based motif.

C.Xu, E.Gagnon, M.E.Call, J.R.Schnell, C.D.Schwieters, C.V.Carman, J.J.Chou, K.W.Wucherpfennig.

ABSTRACT

Many immune system receptors signal through cytoplasmic tyrosine-based motifs (ITAMs), but how receptor ligation results in ITAM phosphorylation remains unknown. Live-cell imaging studies showed a close interaction of the CD3epsilon cytoplasmic domain of the T cell receptor (TCR) with the plasma membrane through fluorescence resonance energy transfer between a C-terminal fluorescent protein and a membrane fluorophore. Electrostatic interactions between basic CD3epsilon residues and acidic phospholipids enriched in the inner leaflet of the plasma membrane were required for binding. The nuclear magnetic resonance structure of the lipid-bound state of this cytoplasmic domain revealed deep insertion of the two key tyrosines into the hydrophobic core of the lipid bilayer. Receptor ligation thus needs to result in unbinding of the CD3epsilon ITAM from the membrane to render these tyrosines accessible to Src kinases. Sequestration of key tyrosines into the lipid bilayer represents a previously unrecognized mechanism for control of receptor activation.

Selected figure(s)

Figure 3.
Figure 3. The CD3 epsilon Cytoplasmic Domain Is Bound to the Inner Leaflet of the Plasma Membrane
(A and C) The FRET efficiency was determined for transfectants expressing the CD3 epsilon WT or a CD3 epsilon mutant cytoplasmic domain (Emut1+2) (10 cells/construct, error bars indicate SEM) using the quenching approach, as in Figures 2C and 2E. R18-PB: R18 photobleached.
(B and D) The donor dequenching method was used to measure the FRET efficiency for the same transfectants (20 cells shown here from one experiment), as in Figures 2D and 2F.

Figure 7.
Figure 7. Membrane Binding Renders the Tyrosines of CD3 epsilon Inaccessible to Lck
(A) Lipid binding prevents tyrosine phosphorylation of CD3 epsilon [CD]. The tyrosine residues of CD3 epsilon [CD] were efficiently phosphorylated by Lck in an in vitro kinase assay. Addition of POPG/DHPC bicelles but not control POPC/DHPC bicelles prevented tyrosine phosphorylation. Western blots were probed with a phospho-tyrosine antibody (biotinylated P-Tyr-100 and streptavidin-horseradish peroxidase, SA-HRP) and a CD3 epsilon [CD] antibody (CD3 epsilon m20 and anti-goat IgG-HRP).
(B) Neither endogenous CD3 epsilon nor the HA-KIR-CD3 epsilon [CD]-TFP reporter protein are basally phosphorylated. HA-KIR-CD3 epsilon [CD]-TFP transfected Jurkat cells were solubilized using 1% NP40 and proteins were immunoprecipitated with CD3ζ (6B10.2), CD3 epsilon (UCHT1), HA (3F10), or FLAG (M2, isotype control) antibodies. Phosphorylated and total proteins were detected with a phospho-tyrosine antibody (biotinylated P-Tyr-100 and SA-HRP, upper panel), a CD3 epsilon [CD] antibody (CD3 epsilon m20 and anti-goat IgG-HRP, which detects CD3 epsilon and the reporter protein), or an antibody to the ζ chain (anti-CD3ζ 6B10.2-HRP, lower panel). SDS-PAGE was performed under nonreducing conditions.

The above figures are reprinted from an Open Access publication published by Cell Press: Cell (2008, 135, 702-713) copyright 2008.

Figures were selected by an automated process.