In the Drosophila immune response, bacterial derived diaminopimelic acid-type peptidoglycan binds the receptors PGRP-LC and PGRP-LE, which through interaction with the adaptor protein Imd leads to activation of the NF-κB homolog Relish and robust antimicrobial peptide gene expression. PGRP-LC, PGRP-LE, and Imd each contain a motif with some resemblance to the RIP Homotypic Interaction Motif (RHIM), a domain found in mammalian RIPK proteins forming functional amyloids during necroptosis. Here we found that despite sequence divergence, these Drosophila cryptic RHIMs formed amyloid fibrils in vitro and in cells. Amyloid formation was required for signaling downstream of Imd, and in contrast to the mammalian RHIMs, was not associated with cell death. Furthermore, amyloid formation constituted a regulatable step and could be inhibited by Pirk, an endogenous feedback regulator of this pathway. Thus, diverse sequence motifs are capable of forming amyloidal signaling platforms, and the formation of these platforms may present a regulatory point in multiple biological processes.

在果蝇的免疫反应中，细菌衍生的二氨基庚二酸型肽聚糖与受体PGRP-LC和PGRP-LE结合，通过与衔接蛋白Imd的相互作用导致NF-κB同源物Relish的活化和强大的抗菌肽基因表达。PGRP-LC，PGRP-LE和Imd各自包含一个与RIP同型相互作用基序（RHIM）相似的基序，该基序在哺乳动物RIPK蛋白中发现，在坏死病期间形成功能性淀粉样蛋白。在这里，我们发现尽管有序列差异，但这些果蝇隐性RHIMs在体外形成了淀粉样原纤维。和在细胞中。淀粉样蛋白形成是Imd下游信号转导所必需的，与哺乳动物RHIM相反，它与细胞死亡无关。此外，淀粉样蛋白的形成构成可调节的步骤，并且可以被该途径的内源性反馈调节剂Pirk抑制。因此，多样的序列基序能够形成淀粉样蛋白信号平台，并且这些平台的形成可能在多个生物学过程中呈现出调节点。