C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation

SummaryAn organisms’ ability to adapt to heat can be key to its survival. Cells adapt to temperature shifts by adjusting lipid desaturation levels and the fluidity of membranes in a process that is thought to be controlled cell autonomously. We have discovered that subtle, step-wise increments in ambient temperature can lead to the conserved heat shock response being activated in head neurons of C. elegans. This response is exactly opposite to the expression of the lipid desaturase FAT-7 in the worm’s gut. We find that the over-expression of the master regulator of this response, Hsf-1, in head neurons, causes extensive fat remodeling to occur across tissues. These changes include a decrease in FAT-7 expression and a shift in the levels of unsaturated fatty acids in the plasma membrane. These shifts are in line with membrane fluidity requirements to survive in warmer temperatures. We have identified that the cGMP receptor, TAX-2/TAX-4, as well as TGF-β/BMP signaling, as key players in the transmission of neuronal stress to peripheral tissues. This is the first study to suggest that a thermostat-based mechanism can centrally coordinate membrane fluidity in response to warm temperatures across tissues in multicellular animals.

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Rab8 and Rabin8-Mediated Tumor Formation by Hyperactivated EGFR Signaling via FGFR Signaling

International Journal of Molecular Sciences ◽

10.3390/ijms21207770 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7770

Author(s):

Junghwa Choi ◽

Jee Young Sung ◽

Saerom Lee ◽

Jungyoen Yoo ◽

Christopher Rongo ◽

...

Keyword(s):

Growth Factor Receptor ◽

Tumor Model ◽

Tumor Formation ◽

Rab Proteins ◽

Egfr Signaling ◽

Vulval Development ◽

C Elegans ◽

Exon 19 Deletion ◽

Epidermal Growth ◽

Egfr Tki

The epidermal growth factor receptor (EGFR) signaling is important for normal development, such as vulval development in Caenorhabditis elegans, and hyperactivation of the EGFR is often associated with cancer development. Our previous report demonstrated the multivulva (Muv) phenotype, a tumor model in C. elegans (jgIs25 strain) by engineering LET-23/EGFR with a TKI-resistant human EGFR T790-L858 mutant. Because Rab proteins regulate vesicle transport, which is important for receptor signaling, we screened the RNAi in the jgIs25 strain to find the Rabs critical for Muv formation. Herein, we show that rab-8 RNAi and the rab-8 (-/-) mutation effectively reduce Muv formation. We demonstrate that RABN-8, an ortholog of Rabin8, known as a GEF for Rab8, is also required for Muv formation by promoting the secretion of EGL-17/FGF from vulval precursor cells. In addition, FGFR inhibitors decreased Muv formation mediated by mutant EGFR. Our data suggest that Rab8 and Rabin8 mediate Muv formation through FGF secretion in the EGFR-TKI-resistant nematode model. Furthermore, FGFR-TKIs more effectively inhibit the growth of lung cancer cell lines in H1975 (EGFR T790M-L858R; EGFR-TKI-resistant) than H522 (wild-type EGFR) and H1650 (EGFR exon 19 deletion; EGFR-TKI-sensitive) cells, suggesting that FGFR-TKIs could be used to control cancers with EGFR-TKI-resistant mutations.

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Mechanism of Interaction of BMP and Insulin Signaling in C. elegans Development and Homeostasis

10.1101/777805 ◽

2019 ◽

Author(s):

James F. Clark ◽

Emma J. Ciccarelli ◽

Gehan Ranepura ◽

Muhammad S. Hasan ◽

Alicia Meléndez ◽

...

Keyword(s):

Bmp Signaling ◽

Lipid Homeostasis ◽

Signaling Crosstalk ◽

C Elegans ◽

Morphogenetic Protein ◽

Autophagy Induction ◽

Dauer Formation ◽

And Function ◽

Modes Of Interaction ◽

Molecular Components

AbstractA small number of peptide growth factor ligands are used repeatedly in development and homeostasis to drive programs of cell differentiation and function. Cells and tissues must integrate inputs from these diverse signals correctly, while failure to do so leads to pathology, reduced fitness, or death. Previous work using the nematode C. elegans identified an interaction between the bone morphogenetic protein (BMP) and insulin/IGF-1-like signaling (IIS) pathways in the regulation of lipid homeostasis. The molecular components required for this interaction, however, were not known. Here we report that INS-4, one of 40 insulin-like peptides (ILPs), is specifically regulated by BMP signaling to modulate fat accumulation. Furthermore, we find that the IIS transcription factor DAF-16/FoxO, but not SKN-1/Nrf, acts downstream of BMP signaling in lipid homeostasis. Interestingly, BMP activity alters sensitivity of these two transcription factors to IIS-promoted cytoplasmic retention in opposite ways. Finally, we probe the extent of BMP and IIS interactions by testing two additional IIS functions, dauer formation and autophagy induction. Coupled with our previous work and that of other groups, we conclude that BMP and IIS pathways have at least three modes of interaction: independent, epistatic, and antagonistic. The molecular interactions we identify provide new insight into mechanisms of signaling crosstalk and potential therapeutic targets for IIS-related pathologies such as diabetes and metabolic syndrome.

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The C. elegans SMOC-1 protein acts cell non-autonomously to promote bone morphogenetic protein signaling

10.1101/416669 ◽

2018 ◽

Author(s):

Melisa S. DeGroot ◽

Herong Shi ◽

Alice Eastman ◽

Alexandra N. McKillop ◽

Jun Liu

Keyword(s):

Body Size ◽

Bone Morphogenetic Protein ◽

Calcium Binding ◽

Binding Protein ◽

Calcium Binding Protein ◽

Bmp Signaling ◽

C Elegans ◽

Morphogenetic Protein ◽

Positive Modulator ◽

Bmp Pathway

ABSTRACTBone morphogenetic protein (BMP) signaling regulates many different developmental and homeostatic processes in metazoans. The BMP pathway is conserved in Caenorhabditis elegans, and is known to regulate body size and mesoderm development. We have identified the C. elegans smoc-1 (Secreted MOdular Calcium binding protein-1) gene as a new player in the BMP pathway. smoc-1(0) null mutants have a small body size, while overexpression of smoc-1 led to a long body size and increased expression of the RAD-SMAD BMP reporter, suggesting that SMOC-1 acts as a positive modulator of BMP signaling. Using double mutant analysis, we showed that SMOC-1 antagonizes the function of the glypican LON-2 and acts through the BMP ligand DBL-1 to regulate BMP signaling. Moreover, SMOC-1 appears to specifically regulate BMP signaling without significant involvement in a TGFβ-like pathway that regulates dauer development. We found that smoc-1 is expressed in multiple tissues, including cells of the pharynx, intestine, and posterior hypodermis, and that the expression of smoc-1 in the intestine is positively regulated by BMP signaling. We further established that SMOC-1 functions cell non-autonomously to regulate body size. Human SMOC1 and SMOC2 can each partially rescue the smoc-1(0) mutant phenotype, suggesting that SMOC-1’s function in modulating BMP signaling is evolutionarily conserved. Together, our findings highlight a conserved role of SMOC proteins in modulating BMP signaling in metazoans.ARTICLE SUMMARYBMP signaling is critical for development and homeostasis in metazoans, and is under tight regulation. We report the identification and characterization of a Secreted MOdular Calcium binding protein SMOC-1 as a positive modulator of BMP signaling in C. elegans. We established that SMOC-1 antagonizes the function of LON-2/glypican and acts through the DBL-1/BMP ligand to promote BMP signaling. We identified smoc-1-expressing cells, and demonstrated that SMOC-1 acts cell non-autonomously and in a positive feedback loop to regulate BMP signaling. We also provide evidence suggesting that the function of SMOC proteins in the BMP pathway is conserved from worms to humans.

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C. elegans DBL-1/BMP Regulates Lipid Accumulation via Interaction with Insulin Signaling

10.1101/191049 ◽

2017 ◽

Author(s):

JF Clark ◽

M Meade ◽

G Ranepura ◽

DH Hall ◽

C Savage-Dunn

Keyword(s):

Lipid Metabolism ◽

Lipid Droplet ◽

Lipid Accumulation ◽

Metabolic Disorders ◽

Bmp Signaling ◽

Lipid Homeostasis ◽

Metabolic Homeostasis ◽

C Elegans ◽

Lipid Droplet Size ◽

Lipid Stores

AbstractMetabolic homeostasis is coordinately controlled by diverse inputs, which must be understood to combat metabolic disorders. Here we introduce DBL-1, the C. elegans BMP2/4 homolog, as a significant regulator of lipid homeostasis. We used neutral lipid staining and a lipid droplet marker to demonstrate that both increases and decreases in DBL-1/BMP signaling result in reduced lipid stores and lipid droplet count. We find that lipid droplet size, however, correlates positively with the level of DBL 1/BMP signaling. Regulation of lipid accumulation in the intestine occurs through non-cell-autonomous signaling, since expression of SMA-3, a Smad signal transducer, in the epidermis (hypodermis) is sufficient to rescue the loss of lipid accumulation. Finally, genetic evidence indicates that DBL-1/BMP functions upstream of Insulin/IGF-1 Signaling (IIS) in lipid metabolism. We conclude that BMP signaling regulates lipid metabolism in C. elegans through inter-organ signaling to IIS, shedding light on a less well-studied regulatory mechanism for metabolic homeostasis.

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Conditional CRISPR-Cas Genome Editing in Drosophila to Generate Intestinal Tumors

Cells ◽

10.3390/cells10113156 ◽

2021 ◽

Vol 10 (11) ◽

pp. 3156

Author(s):

Shivohum Bahuguna ◽

Siamak Redhai ◽

Jun Zhou ◽

Tianyu Wang ◽

Fillip Port ◽

...

Keyword(s):

Genome Editing ◽

Tumor Formation ◽

Bmp Signaling ◽

Fine Tuning ◽

Expression Vectors ◽

Intestinal Tumors ◽

Editing Efficiency ◽

Guide Rnas ◽

Test Genome

CRISPR-Cas has revolutionized genetics and extensive efforts have been made to enhance its editing efficiency by developing increasingly more elaborate tools. Here, we evaluate the CRISPR-Cas9 system in Drosophila melanogaster to assess its ability to induce stem cell-derived tumors in the intestine. We generated conditional tissue-specific CRISPR knockouts using different Cas9 expression vectors with guide RNAs targeting the BMP, Notch, and JNK pathways in intestinal progenitors such as stem cells (ISCs) and enteroblasts (EBs). Perturbing Notch and BMP signaling increased the proliferation of ISCs/EBs and resulted in the formation of intestinal tumors, albeit with different efficiencies. By assessing both the anterior and posterior regions of the midgut, we observed regional differences in ISC/EB proliferation and tumor formation upon mutagenesis. Surprisingly, high continuous expression of Cas9 in ISCs/EBs blocked age-dependent increase in ISCs/EBs proliferation and when combined with gRNAs targeting tumor suppressors, it prevented tumorigenesis. However, no such effects were seen when temporal parameters of Cas9 were adjusted to regulate its expression levels or with a genetically modified version, which expresses Cas9 at lower levels, suggesting that fine-tuning Cas9 expression is essential to avoid deleterious effects. Our findings suggest that modifications to Cas9 expression results in differences in editing efficiency and careful considerations are required when choosing reagents for CRISPR-Cas9 mutagenesis studies. In summary, Drosophila can serve as a powerful model for context-dependent CRISPR-Cas based perturbations and to test genome-editing systems in vivo.

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The C. elegans TspanC8 tetraspanin TSP-14 exhibits isoform-specific localization and function

10.1101/2021.11.10.468015 ◽

2021 ◽

Author(s):

Zhiyu Liu ◽

Herong Shi ◽

Jun Liu

Keyword(s):

Amino Acids ◽

Expression Patterns ◽

Basolateral Membrane ◽

Living Organism ◽

Distribution Patterns ◽

Biochemical Properties ◽

Bmp Signaling ◽

Mesoderm Development ◽

C Elegans

Tetraspanin proteins are a unique family of highly conserved four-pass transmembrane proteins in metazoans. While much is known about their biochemical properties, the in vivo functions and distribution patterns of different tetraspanin proteins are less understood. Previous studies have shown that two paralogous tetraspanins that belong to the TspanC8 subfamily, TSP12 and TSP-14, function redundantly to promote both Notch signaling and bon morphogenetic protein (BMP) signaling in C. elegans. TSP-14 has two isoforms, TSP-14A and TSP-14B, where TSP-14B has an additional 24 amino acids at its N-terminus compared to TSP-14A. By generating isoform specific knock-ins and knock-outs using CRISPR, we found that TSP-14A and TSP-14B share distinct as well as overlapping expression patterns and functions. While TSP14A functions redundantly with TSP-12 to regulate body size and embryonic and vulva development, TSP-14B primarily functions redundantly with TSP-12 to regulate postembryonic mesoderm development. Importantly, TSP-14A and TSP-14B exhibit distinct subcellular localization patterns. TSP-14A is localized apically and on early and late endosomes. TSP-14B is localized to the basolateral cell membrane. We further identified a di-leucine motif within the Nterminal 24 amino acids of TSP-14B that serves as a basolateral membrane targeting sequence, and showed that the basolateral membrane localization of TSP-14B is important for its function. Our work highlights the diverse and intricate functions of TspanC8 tetraspanins in C. elegans, and demonstrates the importance of dissecting the functions of these important proteins in an intact living organism.

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The Drosophila gene Medea demonstrates the requirement for different classes of Smads in dpp signaling

Development ◽

10.1242/dev.125.8.1519 ◽

1998 ◽

Vol 125 (8) ◽

pp. 1519-1528 ◽

Cited By ~ 5

Author(s):

P. Das ◽

L.L. Maduzia ◽

H. Wang ◽

A.L. Finelli ◽

S.H. Cho ◽

...

Keyword(s):

Transforming Growth Factor Beta ◽

Transforming Growth Factor ◽

Human Tumor ◽

Suppressor Gene ◽

Bmp Signaling ◽

Class I ◽

Tgf Beta ◽

C Elegans ◽

Sequence Similarities ◽

Close Homolog

Signals from transforming growth factor-beta (TGF-beta) ligands are transmitted within the cell by members of the Smad family, which can be grouped into three classes based on sequence similarities. Our previous identification of both class I and II Smads functioning in a single pathway in C. elegans, raised the issue of whether the requirement for Smads derived from different classes is a general feature of TGF-beta signaling. We report here the identification of a new Drosophila class II Smad, Medea, a close homolog of the human tumor-suppressor gene DPC4. Embryos from germline clones of both Medea and Mad (a class I Smad) are ventralized, as are embryos null for the TGF-beta-like ligand decapentaplegic (dpp). Loss of Medea also blocks dpp signaling during later development, suggesting that Medea, like Mad, is universally required for dpp signaling. Furthermore, we show that the necessity for these two closely related, non-redundant Smads, is due to their different signaling properties - upon activation of the Dpp pathway, Mad is required to actively translocate Medea into the nucleus. These results provide a paradigm for, and distinguish between, the requirement for class I and II Smads in Dpp/BMP signaling.

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