A Feedback Regulatory Loop Involving dTrbd/dTak1 in Controlling IMD Signaling in Drosophila Melanogaster

Abstract

Negative regulators of the inflammatory responses are essential for the maintenance of immune homeostasis and organismal fitness. In Drosophila, the deubiquitinase (Dub) dTrbd selectively restricts the K63-linked ubiquitination modification of dTak1, a pivotal kinase of the IMD signaling pathway, to regulate the IMD innate immune response. However, which domain and how it functions to enable dTrbd’s activity remain unexplored. Here, we provide compelling evidence showing that the NZF domain of dTrbd is essential for its association with dTak1. Meanwhile, the Linker region of dTrbd is involved in modulating its condensation, a functional state representing the Dub enzymatical activity of dTrbd. Of interest, the activated IMD signals following bacterial stimuli enhance the dTrbd/dTak1 interaction, as well as the condensate assembly and Dub enzymatical activity of dTrbd. Collectively, our studies shed light on the dual mechanisms by which the IMD signaling-mediated feedback loop of dTrbd/dTak1 precisely regulates the innate immune response in Drosophila.

Sex-specific deubiquitylation drives immune-related neurodegeneration inDrosophila

“…In mammals, A20 is a negative regulator of IKK/NF-κB activation (Lork et al, 2017). In Drosophila, knocking out the trbd ORF leads to over activation of IKK-induced NF-κB signalling (Fernando et al, 2014; Hua et al, 2022; Kounatidis et al, 2017). A20 mediates Met1, Lys48 and Lys63 ubiquitin chains to regulate inflammation (Lork et al, 2017; Wertz et al, 2015) and Trabid can regulate Lys63 ubiquitin chains in vitro (Fig 1D) and in vivo (Fernando et al, 2014; Licchesi et al, 2012).…”

“…One of the regulators of NF-κB-mediated inflammation is the DUB Trabid (Fernando et al, 2014; Hua et al, 2022; Kounatidis et al, 2017). In Drosophila, Trabid acts as a negative regulator of the IMD/NF-κB pathway, homologous to TNFR1/NF-κB pathway (Fernando et al, 2014; Hua et al, 2022; Kounatidis et al, 2017).…”

“…One of the regulators of NF-κB-mediated inflammation is the DUB Trabid (Fernando et al, 2014; Hua et al, 2022; Kounatidis et al, 2017). In Drosophila, Trabid acts as a negative regulator of the IMD/NF-κB pathway, homologous to TNFR1/NF-κB pathway (Fernando et al, 2014; Hua et al, 2022; Kounatidis et al, 2017). Deletion of trabid ( trbd ), de-represses the pathway and results in increased neuroinflammation, locomotion defects and ultimately brain lesions associated with age-dependent neurodegeneration (Kounatidis et al, 2017).…”

Endoplasmic reticulum-associated protein degradation contributes to Toll innate immune defense in Drosophila melanogaster

“…RT-qPCR assays were performed according to protocols described previously ( 50 ). Briefly, whole flies (male) or dissected fat bodies were homogenized in the RNA-easy Isolation Reagent (Vazyme) using glass beads.…”

A conserved role of bam in maintaining metabolic homeostasis via regulating intestinal microbiota in Drosophila

“…Western blotting assays were performed according to methods described previously ( Hua et al, 2022 ). The following antibodies were utilized for Western blotting: Bam (mouse, 1:3000, DSHB), Actin (mouse, 1:5000, Cat#A4700; Sigma), and Goat anti-Mouse IgG H&L (1:3000, Cat#ab150078; Abcam).…”