Fig. 6. TCR signals branch at the level of the plasma membrane leading to the assembly of multiple signalosomes.

a, For each of the 366 high-confidence bait-prey interactions, we calculated the maximun number of copies that form per CD4⁺ T cell over 600 s of TCR stimulation and showed their distribution in the lower panel. It ranged from 0.4 to 7.0 x 10⁴ copies per T cell with a median close to 1.1 x 10² copies per T cell. The high-confidence bait-prey interactions that involve a prey corresponding to a receptor (CD3ε, CD5, CD6, BTLA) or an adaptor (LAT, LAX1) associated with the T cell plasma membrane are shown in the upper panel. b, Following TCR engagement, signalosomes involving CBL, CBLB and VAV1 nucleate around the CD5 and CD6 transmembrane receptors in numbers comparable to those that form around the LAT adaptor via SLP-76, SHIP1 and THEMIS intermediates. Also shown are the BTLA coinhibitory receptor and the LAX1 adaptor that assemble signalosomes involving SHP1 and CBLB, respectively. Tyrosine residues (red dots) present in the intracytoplasmic segments of the depicted receptors and adaptors are phosphorylated by the LCK or ZAP70 PTK that associate with active TCR (dashed red arrows). Baits and preys are denoted using red and blue boxes, respectively. The maximum number (copies per T cell) of bait-prey complexes reached over the course of 600 s of TCR stimulation is specified over the arrows connecting the baits and the preys. For instance, the maximm number of CD5-CBLB complexes reached per T cell over 600 s of TCR stimulation is approximately 353.