Reinke AW et al. (2017) Sci Adv "In vivo mapping of tissue- and subcellular-specific proteomes in Caenorhabditis elegans."

Bennett EJ, Reinke AW, Troemel ER, Mak R

[Sci Adv, 2017]

Multicellular organisms are composed of tissues that have distinct functions requiring specialized proteomes. To define the proteome of a live animal with tissue and subcellular resolution, we adapted a localized proteomics technology for use in the multicellular model organism Caenorhabditis elegans. This approach couples tissue- and location-specific expression of the enzyme ascorbate peroxidase (APX), which enables proximity-based protein labeling in vivo, and quantitative proteomics to identify tissue- and subcellular-restricted proteomes. We identified and localized more than 3000 proteins from strains of C. elegans expressing APX in either the nucleus or cytoplasm of the intestine, epidermis, body wall muscle, or pharyngeal muscle. We also identified several hundred proteins that were specifically localized to one of the four tissues analyzed or specifically localized to the cytoplasm or the nucleus. This approach resulted in the identification both of proteins with previously characterized localizations and of those not known to localize to the nucleus or cytoplasm. Further, we confirmed the tissue- and subcellular-specific localization of a subset of identified proteins using green fluorescent protein tagging and fluorescence microscopy, validating our in vivo proximity-based proteomics technique. Together, these results demonstrate a new approach that enables the tissue- and subcellular-specific identification and quantification of proteins within a live animal.

Reinke AW et al. (2013) Science "Networks of bZIP protein-protein interactions diversified over a billion years of evolution."

Reinke AW, Ashenberg O, Keating AE, Baek J

[Science, 2013]

Differences in biomolecular sequence and function underlie dramatic ranges of appearance and behavior among species. We studied the basic region-leucine zipper (bZIP) transcription factors and quantified bZIP dimerization networks for five metazoan and two single-cell species, measuring interactions in vitro for 2891 protein pairs. Metazoans have a higher proportion of heteromeric bZIP interactions and more network complexity than the single-cell species. The metazoan bZIP interactomes have broadly similar structures, but there has been extensive rewiring of connections compared to the last common ancestor, and each species network is highly distinct. Many metazoan bZIP orthologs and paralogs have strikingly different interaction specificities, and some differences arise from minor sequence changes. Our data show that a shifting landscape of biochemical functions related to signaling and gene expression contributes to species diversity.

Reinke AW et al. (2017) Nat Commun "Identification of microsporidia host-exposed proteins reveals a repertoire of rapidly evolving proteins."

Troemel ER, Reinke AW, Bennett EJ, Balla KM

[Nat Commun, 2017]

Pathogens use a variety of secreted and surface proteins to interact with and manipulate their hosts, but a systematic approach for identifying such proteins has been lacking. To identify these 'host-exposed' proteins, we used spatially restricted enzymatic tagging followed by mass spectrometry analysis of Caenorhabditis elegans infected with two species of Nematocida microsporidia. We identified 82 microsporidia proteins inside of intestinal cells, including several pathogen proteins in the nucleus. These microsporidia proteins are enriched in targeting signals, are rapidly evolving and belong to large Nematocida-specific gene families. We also find that large, species-specific families are common throughout microsporidia species. Our data suggest that the use of a large number of rapidly evolving species-specific proteins represents a common strategy for microsporidia to interact with their hosts. The unbiased method described here for identifying potential pathogen effectors represents a powerful approach to study a broad range of pathogens.