Drosophila EYA Regulates the Immune Response against DNA through an Evolutionarily Conserved Threonine Phosphatase Motif

Abstract

Innate immune responses against DNA are essential to counter both pathogen infections and tissue damages. Mammalian EYAs were recently shown to play a role in regulating the innate immune responses against DNA. Here, we demonstrate that the unique Drosophila eya gene is also involved in the response specific to DNA. Haploinsufficiency of eya in mutants deficient for lysosomal DNase activity (DNaseII) reduces antimicrobial peptide gene expression, a hallmark for immune responses in flies. Like the mammalian orthologues, Drosophila EYA features a N-terminal threonine and C-terminal tyrosine phosphatase domain. Through the generation of a series of mutant EYA fly strains, we show that the threonine phosphatase domain, but not the tyrosine phosphatase domain, is responsible for the innate immune response against DNA. A similar role for the threonine phosphatase domain in mammalian EYA4 had been surmised on the basis of in vitro studies. Furthermore EYA associates with IKKβ and full-length RELISH, and the induction of the IMD pathway-dependent antimicrobial peptide gene is independent of SO. Our data provide the first in vivo demonstration for the immune function of EYA and point to their conserved immune function in response to endogenous DNA, throughout evolution.

Retinal Axon Guidance Requires Integration of Eya and the Jak/Stat Pathway into Phosphotyrosine-Based Signaling Circuitries in Drosophila

“…Another possibility is that Eya might modulate the composition or function of such complexes via its phosphothreonine phosphatase activity. Eya's threonine phosphatase activity has been implicated in innate immunity in both mammals and Drosophila, and although substrates have not been identified, cytoplasmic activity was implied by the identified interactions (Okabe et al 2009;Liu et al 2012). Intriguingly, the Jak/Stat pathway is relevant to innate immunity in both Drosophila and mammals (reviewed in Perrimon 2004 andO'Shea andPlenge 2012).…”

“…Although Eya's tyrosine phosphatase is not required for normal development in Drosophila (Jin et al 2013), in mammals it dephosphorylates H2AX to promote repair and survival in response to DNA damage (Cook et al 2009;Krishnan et al 2009) and aPKCz to direct lung epithelial polarity and morphogenesis (El-Hashash et al 2012). Eya's threonine phosphatase is less well characterized, but appears to act both cytoplasmically to regulate innate immunity and nuclearly to provide transactivation and regulate the activity of other transcription factors (Okabe et al 2009;Liu et al 2012;Xu et al 2014;Jin and Mardon 2016).…”

The Chromatin Regulator DMAP1 Modulates Activity of the Nuclear Factor κB (NF-κB) Transcription Factor Relish in the Drosophila Innate Immune Response

“…gut) (12). Further, it is not only activated by Gram-negative bacteria, but can react in the absence of infection to endogenous ligands, namely DNA (13,14).…”

Multiple Functions of the Eya Phosphotyrosine Phosphatase

“…Whereas earlier studies had relied on overexpression-and misexpression-based genetic assays to show compromised output from phosphatase-dead Eya (39,40,49,56,57), Percentages of amino acid identities and similarities were calculated using LALIGN and are shown above and below the diagonal white line, respectively. Percentile bins are colored from dark to light in descending order.…”

“…3). Although the catalytic mechanism and protein fold remain unknown, two follow-up studies identified mouse Eya3 as having the strongest in vitro threonine phosphatase activity of the four Eya paralogs, defined more precisely the sequence boundaries of the domain (93), and showed that both Eya's threonine phosphatase activity and its role in regulating innate immunity are likely to be conserved in Drosophila (57). The latter conclusion was based on heat shockdriven rescue transgenes, and so given the hard lesson with the tyrosine phosphatase activity (55), it will need to be confirmed with genomic constructs.…”