Abstract

A protein domain (Toll and Interleukin-1 receptor [TIR]-like) with homology to animal TIRs mediates immune signaling in
prokaryotes and eukaryotes. Here, we present an overview of TIR evolution and the molecular versatility of TIR domains in
different protein architectures for host protection against microbial attack. Plant TIR-based signaling emerges as being central
to the potentiation and effectiveness of host defenses triggered by intracellular and cell-surface immune receptors.
Equally relevant for plant fitness are mechanisms that limit potent TIR signaling in healthy tissues but maintain preparedness
for infection. We propose that seed plants evolved a specialized protein module to selectively translate TIR enzymatic
activities to defense outputs, overlaying a more general function of TIRs.

Read more at The Plant Cell 2022: 00: 1-18