Skip to main content
. 2024 Jun 5;12:RP89306. doi: 10.7554/eLife.89306

Figure 2. Identification of ER exit motif of LAT.

(A) Schematic of LAT and the truncated versions used here. Inset shows a putative COPII association motif and the evolutionary conservation of residues 144–153 of hLAT. (B) Temporal dependence of the fraction of ER-positive cells for LAT truncations. Deletion of a region comprised of residues 140–185 leads to slow ER exit. (C) Fitted ER exit kinetics for the constructs represented in panel C. Deletion of amino acids 140–185 slows ER exit kinetics by ~fourfold. (D) Temporal dependence of fraction of ER-positive cells with point mutations of ΦxΦxΦ motif. Mutations of key residues within the motif slow ER exit kinetics. (E) Fitted ER exit kinetics for point mutants in panel D. (F) Insertion of AaPsA motif into LAT-TMD accelerates ER exit kinetics. (B and D) show a representative experiment with exponential decay fits; points in C, E, and F represent t1/2 values of ER exit from fits of independent repeats with >20 cells/experiment. **p<0.01, ***p<0.001, nsp >0.05. Original data quantification can be found in the Source Data files.

Figure 2—source data 1. Quantification of the temporal dependence of the fraction of ER-positive cells on cytosolic domains.
Figure 2—source data 2. Quantification of the ER exit kinetics for the constructs represented in panel B.
Figure 2—source data 3. Quantification of the temporal dependence of the fraction of ER-positive cells point mutations in the potential COP-II recognition motif of the cytoslic tail of LAT.
Figure 2—source data 4. Quantification of the fit ER exit kinetics for point mutants in LAT protein show that changes in a single amino acid of the COP-II recognition motif slow down the full-length ER exit to the level of the TMD-only.

Figure 2.

Figure 2—figure supplement 1. COPII binding motif mediates fast ER exit of LAT.

Figure 2—figure supplement 1.

(A) Half-time for ER exit for point mutations in the FxFxF motif of LAT. P148 is critical for fast export from the ER, P151 is not. (B) Evolutionary conservation of cytoplasmic resides of LAT (denoted for residues G33 through the C-terminal N254 of human LAT). Red marks P148 and A150 for comparison.