Journal: bioRxiv
Article Title: Polyubiquitin-dependent recruitment of NEMO/IKKγ into T cell receptor signaling microclusters
doi: 10.1101/617126
Figure Lengend Snippet: A) Jurkat T cells stably transduced with mYFP.NEMO were activated on stimulatory glass surfaces coated with 10 μg/ml anti-CD3 (OKT3), 1 μg/ml rhVCAM1 and/or 10 μg/ml fibronectin, as indicated. Dotted blue arrows, marked ‘P’, identify perinuclear pools of NEMO. Objects marked with a red ‘M’ are typical of the large objects referred to as ‘macroclusters’. Similar patterns were observed in every experiment (n≥3 for each condition). Scale bars: 10 μm. B) Primary human T cell blasts were transduced, stimulated, and imaged as in A. Images are representative of four experiments. C) The lag between local contact initiation and NEMO microcluster formation was calculated for cells captured in the process of spreading. Data are presented as the mean ± SD based on the number of cells examined. 468 clusters were observed in thirteen cells stimulated on anti-CD3 (3, n=8 cells) or anti-CD3 and rhVCAM1 (3-V, n=2 cells). No significant differences were observed between any group of cells and the pool of all conditions, or the cells stimulated on anti-CD3. D) Jurkat T cells stably transduced with mYFP.NEMO were stimulated on anti-CD3 and rhVCAM1 and fixed after five minutes. NEMO clusters were identified algorithmically (see Materials and Methods). The resulting masks are pseudo-colored (green) and superimposed on the raw image (red). Line scans show NEMO intensity (red line) along the indicated white line relative to the cluster masks (shaded green). E) Jurkat T cells were transiently transfected or stably transduced with mYFP.NEMO and imaged on the indicated substrates. NEMO clusters identified as in D were binned into classes based on cluster area. Classes are labeled using the diameter of a circle with an area equivalent to the upper bound of the class. Graphs present the cluster count (upper), the fractional distribution of clusters by class (middle), and the fraction of the NEMO intensity in the imaging plane that is captured within each class (lower). Data are presented as the mean ± SEM, based on the number of cells analyzed. Cluster quantitation was performed using 23 cells stimulated on anti-CD3 and rhVCAM1 and 13 cells stimulated on rhVCAM1 alone. Statistical differences among classes were determined using Student’s T-test: p < 0.05, *; p < 0.01, **; p < 0.001, ***. F) Jurkat cells expressing mYFP.NEMO and NFκB-luciferase plus either mCer3 itself or mCer3 chimeras with WT or kinase-deficient (KR) IKKβ were stimulated as indicated; levels of luciferase were measured to indicate the amount of NF-κB transcription. G) Jurkat T cells stably expressing mYFP.NEMO WT and either mCer3.IKKβ WT or mCer3.IKKβ-K44R (kinase-deficient mutant). Kymographs for each were taken from the region in the white box, and represent 5 minutes in time. H) Model showing the location of NEMO S68 in the context of a NEMO dimer; phosphorylation of this site is predicted to cause destabilization of the IKK complex and dissolution of the NEMO/ IKKβ microcluster.
Article Snippet: The Jurkat human leukemic T cell line E6.1 (TIB-152; RRID:CVCL_0367) and the C305 hybridoma (CRL-2424; RRID:CVCL_K130) were obtained from ATCC (Manassas, VA).
Techniques: Stable Transfection, Transduction, Transfection, Labeling, Imaging, Quantitation Assay, Expressing, Luciferase, Mutagenesis, Phospho-proteomics, Dissolution