Figure 2.

Structure of LILRB4. The LILRB4 gene is localized to the leukocyte receptor cluster on chromosome 19q13.4. The extracellular segment consists of two immunoglobulin-like structural domains, D1 and D2, whose D1–D2 ectodomain employs an unusually blunted 107° interdomain angle for its stabilization via hydrophobic interactions. The intracellular segment, on the other hand, is comprised of three immunoreceptor tyrosine-based inhibitory motifs (ITIM), and within the constituent ITIM motifs, the tyrosines at positions 360, 412 and 442 are phosphorylation sites. Of these, Y412 and Y442 recruit SHP-2 to activate downstream signaling and further exert relevant immune effects (illustrated using www.figdraw.com, accessed on 25 January 2024).