Drosophila Nimrod proteins bind bacteria

Abstract

Engulfment of foreign particles by phagocytes is initiated by the engagement of phagocytic receptors. We have previously reported that NimC1 is involved in the phagocytosis of bacteria in Drosophila melanogaster. We have identified a family of genes, the Nimrod gene superfamily, encoding characteristic NIM domain containing structural homologues of NimC1. In this work we studied the bacterium-binding properties of the Nimrod proteins by using a novel immunofluorescencebased flow cytometric assay. This method proved to be highly reproducible and suitable for investigations of the bacteriumbinding capacities of putative phagocytosis receptors. We found that NimC1, NimA, NimB1 and NimB2 bind bacteria significantly but differently. In this respect they are similar to other NIM domain containing receptors Eater and Draper.

Involvement of the Anopheles gambiae Nimrod gene family in mosquito immune responses

“…Instead, the membrane of E. coli needs to be disrupted by antimicrobial peptides such as cecropin prior to there being a direct interaction between Eater and this bacterium (Chung and Kocks, 2011). Perhaps because of this reason some studies have found that the binding affinities of Nimrod family genes vary depending on whether the assay was carried out in vivo (with a full complement of hemolymph proteins) or in vitro (Chung and Kocks, 2011;Zsamboki et al, 2013).…”

“…Genes in the Nimrod B subclass encode several NIM repeats but do not encode a transmembrane domain. Not much is known about the biology of Nimrod B genes, but a recent study showed that NimB2 binds E. coli in vitro, and that NimB1 binds both E. coli and Staphylococcus epidermidis (Zsamboki et al, 2013). Finally, genes in the Nimrod C subclass encode multiple NIM repeats and a transmembrane domain.…”

“…Depletion of Eater decreases bacterial killing in the hemocoel and increases fruit fly mortality following infection. NimC1 is also expressed in hemocytes, can bind E. coli, Serratia marcescens, Xanthomonas campestris, Pseudomonas aeruginosa and Bacillus cereus, and is involved in the phagocytosis of at least E. coli and S. aureus (Kurucz et al, 2007;Zsamboki et al, 2013). Members of this gene family have been identified in multiple insect orders, although their function has only been studied in detail in Drosophila (Ju et al, 2006;Kim et al, 2011;Somogyi et al, 2010).…”

Insect immunology and hematopoiesis

“…For example, some members of the Nimrod gene family encode cell surface receptors with multiple transmembrane domains whereas others encode secreted proteins, and different members of this same protein family also recognize different combinations of pathogens (Estevez-Lao and Hillyer, 2014; Kocks et al, 2005; Kurucz et al, 2007; Zsamboki et al, 2013). Furthermore, some PRRs directly elicit immune effector processes such as phagocytosis and melanization, others activate intracellular signaling pathways that activate the transcription of immune effector genes, and yet others activate both effector and signaling pathways (Choe et al, 2002; Levashina et al, 2001).…”

A novel phagocytic receptor (CgNimC) from Pacific oyster Crassostrea gigas with lipopolysaccharide and gram-negative bacteria binding activity

“…By contrast, Nimrod C subclass receptors possess multiple NIM repeats and a transmembrane domain [19]. Two Nimrod C, Eater and NimC1 (Nimrod C1), have been characterized, and both of them are expressed in hemocytes and contributed to recognition and phagocytosis of bacteria [5,9,10].…”