Together, these data suggest that Fat functions as a cell-surface receptor for the Expanded branch of the conserved Hippo growth control pathway.

Phagocytosis is important during development and in the immune response for the removal of apoptotic cells and pathogens, yet its molecular mechanisms are poorly understood. In Caenorhabditis elegans, the CED2/5/10/12 pathway regulates actin during phagocytosis of apoptotic cells, whereas the role of the CED1/6/7 pathway in phagocytosis is unclear. We report that Undertaker (UTA), a Drosophila Junctophilin protein, is required for Draper (CED-1 homolog)-mediated phagocytosis. Junctophilins couple Ca2+ channels at the plasma membrane to those of the endoplasmic reticulum (ER), the Ryanodine receptors. We place Draper, its adaptor drCed-6, UTA, the Ryanodine receptor Rya-r44F, the ER Ca2+ sensor dSTIM, and the Ca2+-release-activated Ca2+ channel dOrai in the same pathway that promotes calcium homeostasis and phagocytosis. Thus, our results implicate a Junctophilin in phagocytosis and link Draper-mediated phagocytosis to Ca2+ homeostasis, highlighting a previously uncharacterized role for the CED1/6/7 pathway.

ATM is a large, multifunctional protein kinase that regulates responses required for surviving DNA damage: including DNA repair, apoptosis, and cell cycle checkpoints. Here, we show that Drosophila ATM function is essential for normal adult development. Extensive, inappropriate apoptosis occurs in proliferating atm mutant tissues, and in clonally derived atm mutant embryos, frequent mitotic defects were seen. At a cellular level, spontaneous telomere fusions and other chromosomal abnormalities are common in atm larval neuroblasts, suggesting a conserved and essential role for dATM in the maintenance of normal telomeres and chromosome stability. Evidence from other systems supports the idea that DNA double-strand break (DSB) repair functions of ATM kinases promote telomere maintenance by inhibition of illegitimate recombination or fusion events between the legitimate ends of chromosomes and spontaneous DSBs. Drosophila will be an excellent model system for investigating how these ATM-dependent chromosome structural maintenance functions are deployed during development. Because neurons appear to be particularly sensitive to loss of ATM in both flies and humans, this system should be particularly useful for identifying cell-specific factors that influence sensitivity to loss of dATM and are relevant for understanding the human disease, ataxia-telangiectasia.

Summary The Drosophila tumour suppressor gene fat encodes a large cadherin that regulates growth and a form of tissue organization known as planar cell polarity (PCP). Fat regulates growth via the Hippo kinase pathway [1–4], which controls expression of genes promoting cell proliferation and inhibiting apoptosis (reviewed in [5–11]). The Hippo pathway is highly conserved and is implicated in the regulation of mammalian growth and cancer development [12–18]. Genetic studies suggest that Fat activity is regulated by binding to another large cadherin Dachsous (Ds) [19–25]. The tumour suppressor, discs overgrown (dco)/Casein Kinase I δ/ε, also regulates Hippo activity and PCP [1, 26, 27]. The biochemical nature of how Fat, Ds and Dco interact to regulate these pathways is poorly understood. Here we demonstrate that Fat is cleaved to generate 450kDa and 110kDa fragments (Fat450 and Fat110). Fat110 contains the cytoplasmic and transmembrane domain. The cytoplasmic domain of Fat binds Dco, and is phosphorylated by Dco at multiple sites. Importantly, we show Fat forms cis-dimers, and that Fat phosphorylation is regulated by Dachsous and Dco in vivo. We propose that Ds regulates Dco-dependent phosphorylation of Fat and Fat-associated proteins to control Fat signaling in growth and PCP.

Coronavirus disease 2019 is responsible for a global pandemic and has impacted health care accessibility and delivery. Clinic data were reviewed for an STI clinic from September 2019 to May 2020. A significant decrease in rates of STI visits and treatments during the coronavirus disease 2019 pandemic was observed.

Improved reporting standards, and adoption of experimental protocols that emphasize control of experimental bias, are likely to improve understanding and confidence in pain biology.

Many cells die by apoptosis during animal development. Apoptotic cells are rapidly removed through phagocytosis by their neighbors or by macrophages. To genetically dissect this process, we performed an in vivo screen for genes required for efficient phagocytosis of apoptotic cells by Drosophila macrophages and identified pallbearer (pall), which encodes an F box protein. F box proteins generally provide substrate specificity to Skp Cullin F box (SCF) complexes, acting as E3 ligases that target phosphorylated proteins to ubiquitylation and degradation via the 26S proteasome. We showed that Pallbearer functions in an SCF-dependent manner and provided direct evidence of a role for ubiquitylation and proteasomal degradation in phagocytosis of apoptotic corpses in vivo. This work might further our understanding of the regulation of apoptotic cell engulfment and thus our understanding of innate immunity as a whole.

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