Fig. 2
Ii C-terminal TRIM is not necessary for binding to MHCIIs and to egress the ER. a Schematic representation of Δ20 and Δ20TRIM. The lumenal glycosylation sites, CLIP region and TRIM are illustrated on the Ii molecule. Di-leucine endosomal targeting motifs (open circles) were removed following deletion of the first N-terminal cytoplasmic 20 aa (gray box) of p33 in Δ20 and Δ20TRIM mutants. As for p35LIMLTRIM, the TRIM domain was deleted (Δ aa128 to 216 of p33) in the Δ20TRIM mutant and a myc/His-tag was added (detection 9e10 mAb). The Ii top view highlights how the trimerization domains oligomerize. The top view of Δ20TRIM mutant shows the myc tag and trimerization via the TM (grey circles). b Ii Δ20, Δ20TRIM, p35LIML or p35LIMLTRIM were transiently transfected in HEK293T cells. After 48 h, cells were stained to detect surface (black dotted line) and total (black line) Ii using mAbs BU45 or 9e10 (for IiTRIM mutants). c Cells were transfected as above together with DR and stained for surface and total Ii. d Cells from (c) and cells transfected as in (c) together with DM were stained for surface CLIP using CerCLIP.1 Ab. CLIP MFIs (mean fluorescence intensity) are expressed in a bar-chart. Error bars indicate the SD from at least five independent experiments. Student t-tests were performed; *p ≤ 0.001 and **p ≤ 0.05