(A) In a heterotypic activation model, trans
interactions between cells expressing different Toll receptors (purple and
orange) in adjacent stripes could stabilize Toll receptors at vertical
interfaces. (B) In a homotypic inactivation model, trans
interactions between cells expressing the same Toll receptor type could
destabilize Toll receptors at horizontal interfaces. (C) In a homotypic
activation model, trans interactions between cells expressing
the same Toll receptor type could stabilize receptors at horizontal interfaces.
(D) In a partner patterning model, a patterned Toll receptor (purple) and an
unpatterned interaction partner (green) could undergo inhibitory
cis interactions and stabilizing trans
interactions, promoting the enrichment of the partner at vertical interfaces
along the Toll stripe border.