Wu Q et al. (2017) ACS Chem Biol "Hepta-Mutant Staphylococcus aureus Sortase A (SrtA7m) as a Tool for in Vivo Protein Labeling in Caenorhabditis elegans."

Ploegh HL, Truttmann MC, Wu Q

[ACS Chem Biol, 2017]

In vivo protein ligation is of emerging interest as a means of endowing proteins with new properties in a controlled fashion. Tools to site-specifically and covalently modify proteins with small molecules, peptides, or other proteins in living cells are few and far between. Here, we describe the development of a Staphylococcus aureus sortase (SrtA)-based protein ligation approach for site-specific conjugation of fluorescent dyes and ubiquitin (Ub) to modify proteins in Caenorhabditis elegans. Hepta-mutant SrtA (SrtA7m) expressed in C. elegans is functional and supports in vitro sortase reactions in a low-Ca(2+) environment. Feeding SrtA7m-expressing C. elegans with small peptide-based probes such as (Gly)3- biotin or (Gly)3-fluorophores enables in vivo target protein modification. SrtA7m also catalyzes the circularization of suitably modified linear target proteins in vivo and allows the installation of F-box domains on targets to induce their degradation in a ubiquitin-dependent manner. This is a noninvasive method to achieve in vivo protein labeling, protein circularization, and targeted degradation in C. elegans. This technique should improve our ability to monitor and alter the function of intracellular proteins in vivo.

Truttmann MC et al. (2018) Proc Natl Acad Sci U S A "Chaperone AMPylation modulates aggregation and toxicity of neurodegenerative disease-associated polypeptides."

Pincus D, Ploegh HL, Truttmann MC

[Proc Natl Acad Sci U S A, 2018]

Proteostasis is critical to maintain organismal viability, a process counteracted by aging-dependent protein aggregation. Chaperones of the heat shock protein (HSP) family help control proteostasis by reducing the burden of unfolded proteins. They also oversee the formation of protein aggregates. Here, we explore how AMPylation, a posttranslational protein modification that has emerged as a powerful modulator of HSP70 activity, influences the dynamics of protein aggregation. We find that adjustments of cellular AMPylation levels in <i>Caenorhabditis elegans</i> directly affect aggregation properties and associated toxicity of amyloid- (A), of a polyglutamine (polyQ)-extended polypeptide, and of -synuclein (-syn). Expression of a constitutively active <i>C. elegans</i> AMPylase FIC-1(E274G) under its own promoter expedites aggregation of A and -syn, and drastically reduces their toxicity. A deficiency in AMPylation decreases the cellular tolerance for aggregation-prone polyQ proteins and alters their aggregation behavior. Overexpression of FIC-1(E274G) interferes with cell survival and larval development, underscoring the need for tight control of AMPylase activity in vivo. We thus define a link between HSP70 AMPylation and the dynamics of protein aggregation in neurodegenerative disease models. Our results are consistent with a cytoprotective, rather than a cytotoxic, role for such protein aggregates.

van der Voorn L et al. (1990) J Mol Biol "Characterization of a G-protein beta-subunit gene from the nematode Caenorhabditis elegans."

Plasterk RHA, van der Voorn L, Gebbink M, Ploegh HL

[J Mol Biol, 1990]

The gene encoding the beta-subunit of guanine nucleotide binding regulatory proteins (G-proteins) has been cloned from the nematode Caenorhabditis elegans. The predicted 340 amino acid sequence matches the highly conserved amino acid sequences of previously isolated G-protein beta-subunits from mammals and Drosophila. The coding region of the C. elegans beta-subunit gene, which has been mapped to the C. elegans chromosome II, is interrupted by eight introns. Southern analysis indicates that C. elegans has only one beta-subunit gene. A 2.8 kb (1 kb = 10(3) bases or base-pairs) transcript derived from this gene could be detected.

Truttmann MC et al. (2016) PLoS Genet "The Caenorhabditis elegans Protein FIC-1 Is an AMPylase That Covalently Modifies Heat-Shock 70 Family Proteins, Translation Elongation Factors and Histones."

Guo X, Ploegh HL, Cruz VE, Truttmann MC, Engert C, Schwartz TU

[PLoS Genet, 2016]

Protein AMPylation by Fic domain-containing proteins (Fic proteins) is an ancient and conserved post-translational modification of mostly unexplored significance. Here we characterize the Caenorhabditis elegans Fic protein FIC-1 in vitro and in vivo. FIC-1 is an AMPylase that localizes to the nuclear surface and modifies core histones H2 and H3 as well as heat shock protein 70 family members and translation elongation factors. The three-dimensional structure of FIC-1 is similar to that of its human ortholog, HYPE, with 38% sequence identity. We identify a link between FIC-1-mediated AMPylation and susceptibility to the pathogen Pseudomonas aeruginosa, establishing a connection between AMPylation and innate immunity in C. elegans.

Truttmann MC et al. (2016) Proc Natl Acad Sci U S A "Unrestrained AMPylation targets cytosolic chaperones and activates the heat shock response."

Truttmann MC, Krakowiak J, Ploegh HL, Zheng X, Pincus D, Hanke L, Grootveld M, Damon JR

[Proc Natl Acad Sci U S A, 2016]

Protein AMPylation is a conserved posttranslational modification with emerging roles in endoplasmic reticulum homeostasis. However, the range of substrates and cell biological consequences of AMPylation remain poorly defined. We expressed human and Caenorhabditis elegans AMPylation enzymes-huntingtin yeast-interacting protein E (HYPE) and filamentation-induced by cyclic AMP (FIC)-1, respectively-in Saccharomyces cerevisiae, a eukaryote that lacks endogenous protein AMPylation. Expression of HYPE and FIC-1 in yeast induced a strong cytoplasmic Hsf1-mediated heat shock response, accompanied by attenuation of protein translation, massive protein aggregation, growth arrest, and lethality. Overexpression of Ssa2, a cytosolic heat shock protein (Hsp)70, was sufficient to partially rescue growth. In human cell lines, overexpression of active HYPE similarly induced protein aggregation and the HSF1-dependent heat shock response. Excessive AMPylation also abolished HSP70-dependent influenza virus replication. Our findings suggest a mode of Hsp70 inactivation by AMPylation and point toward a role for protein AMPylation in the regulation of cellular protein homeostasis beyond the endoplasmic reticulum.

Queliconi BB et al. (2013) Free Radic Biol Med "Bicarbonate modulates oxidative and functional damage in ischemia-reperfusion."

Augusto O, Kowaltowski AJ, Vaz SM, Brookes PS, Marazzi TB, Queliconi BB, Nehrke K

[Free Radic Biol Med, 2013]

The carbon dioxide/bicarbonate (CO(2)/HCO(3)(-)) pair is the main biological pH buffer. However, its influence on biological processes, and in particular redox processes, is still poorly explored. Here we study the effect of CO(2)/HCO(3)(-) on ischemic injury in three distinct models (cardiac HL-1 cells, perfused rat heart, and Caenorhabditis elegans). We found that, although various concentrations of CO(2)/HCO(3)(-) do not affect function under basal conditions, ischemia-reperfusion or similar insults in the presence of higher CO(2)/HCO(3)(-) resulted in greater functional loss associated with higher oxidative damage in all models. Because the effect of CO(2)/HCO(3)(-) was observed in all models tested, we believe this buffer is an important determinant of oxidative damage after ischemia-reperfusion.

Vandenberg LN et al. (2013) Commun Integr Biol "It's never too early to get it Right: A conserved role for the cytoskeleton in left-right asymmetry."

Lemire JM, Vandenberg LN, Levin M

[Commun Integr Biol, 2013]

For centuries, scientists and physicians have been captivated by the consistent left-right (LR) asymmetry of the heart, viscera, and brain. A recent study implicated tubulin proteins in establishing laterality in several experimental models, including asymmetric chemosensory receptor expression in C. elegans neurons, polarization of HL-60 human neutrophil-like cells in culture, and asymmetric organ placement in Xenopus. The same mutations that randomized asymmetry in these diverse systems also affect chirality in Arabidopsis, revealing a remarkable conservation of symmetry-breaking mechanisms among kingdoms. In Xenopus, tubulin mutants only affected LR patterning very early, suggesting that this axis is established shortly after fertilization. This addendum summarizes and extends the knowledge of the cytoskeleton's role in the patterning of the LR axis. Results from many species suggest a conserved role for the cytoskeleton as the initiator of asymmetry, and indicate that symmetry is first broken during early embryogenesis by an intracellular process.

Filippidis, G et al. (2005) J Phys D Appl Phys "Imaging of Caenorhabditis elegans samples and sub-cellular localization of new generation photosensitizers for photodynamic therapy, using non-linear microscopy."

Filippidis, G, Papazoglou, TG, Voglis, G, Kapsokalyvas, D, Tavernarakis, N, Kouloumentas, C

[J Phys D Appl Phys, 2005]

Two-photon excitation fluorescence (TPEF) and second-harmonic generation (SHG) are relatively new promising tools for the imaging and mapping of biological structures and processes at the microscopic level. The combination of the two image-contrast modes in a single instrument can provide unique and complementary information concerning the structure and the function of tissues and individual cells. The extended application of this novel, innovative technique by the biological community is limited due to the high price of commercial multiphoton microscopes. In this study, a compact, inexpensive and reliable setup utilizing ferntosecond pulses for excitation was developed for the TPEF and SHG imaging of biological samples. Specific cell types of the nematode Caenorhabditis elegans were imaged. Detection of the endogenous structural proteins of the worm, which are responsible for observation of SHG signals, was achieved. Additionally, the binding of different photosensitizers in the HL-60 cell line was investigated, using non-linear microscopy. The sub-cellular localization of photosensitizers of a new generation, very promising for photodynamic therapy (PDT), (Hypericum perforatum L. extracts) was achieved. The sub-cellular localization of these novel photosensitizers was linked with their photodynamic action during PDT, and the possible mechanisms for cell killing have been elucidated.