Lysosomes are central to metabolic homeostasis. The microphthalmia bHLH-LZ transcription factors (MiT/TFEs) family members MITF, TFEB, and TFE3 promote the transcription of lysosomal and autophagic genes and are often deregulated in cancer. Here, we show that the GATOR2 complex, an activator of the metabolic regulator TORC1, maintains lysosomal function by protecting MiT/TFEs from proteasomal degradation independent of TORC1, GATOR1, and the RAG GTPase.
View Article and Find Full Text PDFIn multicellular lives, the differentiation of stem cells and progenitor cells is often accompanied by a transition from glycolysis to mitochondrial oxidative phosphorylation (OXPHOS). However, the underlying mechanism of this metabolic transition remains largely unknown. In this study, we investigate the role of mechanical stress in activating OXPHOS during differentiation of the female germline cyst in Drosophila.
View Article and Find Full Text PDFIndian J Pathol Microbiol
April 2023
Epidermolysis bullosa dystrophica (EBD) is an inherited disease of the structural proteins in the upper dermis, characterized by blister formation at the site of trauma followed by scarring. Skin fragility and blistering are the hallmarks of this disease. Cutaneous squamous cell carcinoma (cSCC) is a dreadful complication in the epidermolysis bullosa (EB) patients and common cause of death.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2023
Target of Rapamycin Complex I (TORC1) is a central regulator of metabolism in eukaryotes that responds to a wide array of negative and positive inputs. The GTPase-activating protein toward Rags (GATOR) signaling pathway acts upstream of TORC1 and is comprised of two subcomplexes. The trimeric GATOR1 complex inhibits TORC1 activity in response to amino acid limitation by serving as a GTPase-activating protein (GAP) for the TORC1 activator RagA/B, a component of the lysosomally located Rag GTPase.
View Article and Find Full Text PDFTarget of Rapamycin Complex 1 (TORC1) is a master regulator that coordinates nutrient status with cell metabolism. The GTPase-activating protein towards Rags complex 1 (GATOR1) inhibits TORC1 activity and protects cells from damage during periods of stress. Here we characterize multiple pathways that regulate the expression of the GATOR1 component Nprl3 in Drosophila.
View Article and Find Full Text PDFThe dysregulation of the metabolic regulator TOR complex I (TORC1) contributes to a wide array of human pathologies. Tuberous sclerosis complex (TSC) is a potent inhibitor of TORC1. Here, we demonstrate that the Rag GTPase acts in both the amino-acid-sensing and growth factor signaling pathways to control TORC1 activity through the regulation of TSC dynamics in HeLa cells and Drosophila.
View Article and Find Full Text PDFJ Am Assoc Nurse Pract
August 2020
Hypomimia/reduced facial mobility in individuals living with Parkinson's disease can lead to negative impressions and judgments by nurse practitioners and other health care practitioners. Negative impressions and judgments can affect the quality of an episode of care. To attenuate automatic judgments, nurse practitioners must self-monitor and correct, recognizing that hypomimia is due to an underlying neurological condition and does not provide information on the personality or character of the person living with Parkinson's.
View Article and Find Full Text PDFAging (Albany NY)
November 2019
Aging and age-related diseases occur in almost all organisms. Recently, it was discovered that the inhibition of target of rapamycin complex 1 (TORC1), a conserved complex that mediates nutrient status and cell metabolism, can extend an individual's lifespan and inhibit age-related diseases in many model organisms. However, the mechanism whereby TORC1 affects aging remains elusive.
View Article and Find Full Text PDFThe TORC1 regulator GATOR1/SEACIT controls meiotic entry and early meiotic events in yeast. However, how metabolic pathways influence meiotic progression in metazoans remains poorly understood. Here we examine the role of the TORC1 regulators GATOR1 and GATOR2 in the response to meiotic double-stranded breaks (DSB) during oogenesis.
View Article and Find Full Text PDFEndoreplication is a cell cycle variant that entails cell growth and periodic genome duplication without cell division, and results in large, polyploid cells. Cells switch from mitotic cycles to endoreplication cycles during development, and also in response to conditional stimuli during wound healing, regeneration, aging, and cancer. In this study, we use integrated approaches in Drosophila to determine how mitotic cycles are remodeled into endoreplication cycles, and how similar this remodeling is between induced and developmental endoreplicating cells (iECs and devECs).
View Article and Find Full Text PDFTORC1 regulates metabolism and growth in response to a large array of upstream inputs. The evolutionarily conserved trimeric GATOR1 complex inhibits TORC1 activity in response to amino acid limitation. In humans, the GATOR1 complex has been implicated in a wide array of pathologies including cancer and hereditary forms of epilepsy.
View Article and Find Full Text PDFTORC1 is a master regulator of metabolism in eukaryotes that responds to multiple upstream signaling pathways. The GATOR complex is a newly defined upstream regulator of TORC1 that contains two sub-complexes, GATOR1, which inhibits TORC1 activity in response to amino acid starvation and GATOR2, which opposes the activity of GATOR1. While the GATOR1 complex has been implicated in a wide array of human pathologies including cancer and hereditary forms of epilepsy, the in vivo relevance of the GATOR2 complex remains poorly understood in metazoans.
View Article and Find Full Text PDFEccrine porocarcinoma, a rare cutaneous malignant tumour accounts for a fraction of sweat gland tumours. This tumour is found to originate from the intraepithelial parts of the sweat glands. It commonly involves the lower extremities in elderly patients and carries an aggressive behaviour.
View Article and Find Full Text PDFHepatoid adenocarcinoma is a rare variant of extra hepatic adenocarcinoma, consisting of foci of both adenomatous and hepatocellular differentiation with morphological and functional resemblance to hepatocellular carcinoma and hence correct diagnosis is a challenge. The most frequent site is stomach. We present this case of hepatoid carcinoma of the gallbladder for its rarity and difficulty in diagnosis which on histology showed papillae, sheets and trabaculae of polygonal cells with eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli with adjacent foci showing high grade dysplasia.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2014
In single-cell eukaryotes the pathways that monitor nutrient availability are central to initiating the meiotic program and gametogenesis. In Saccharomyces cerevisiae an essential step in the transition to the meiotic cycle is the down-regulation of the nutrient-sensitive target of rapamycin complex 1 (TORC1) by the increased minichromosome loss 1/ GTPase-activating proteins toward Rags 1 (Iml1/GATOR1) complex in response to amino acid starvation. How metabolic inputs influence early meiotic progression and gametogenesis remains poorly understood in metazoans.
View Article and Find Full Text PDFPolycomb-group proteins silence gene expression through epigenetic modification of chromatin. In this issue of Developmental Cell, Iovino et al. (2013) demonstrate that Polycomb repressive complex 2 (PRC2) is required for maintenance of oocyte fate by repressing expression of two critical targets, Cyclin E and dacapo, during the early meiotic cycle.
View Article and Find Full Text PDFThe purpose of this article is to discuss the use of music (i.e., two original songs, "Neurotransmitter Twitter" and "Parkinson's Shuffle") to teach aspects of psychopharmacology to students in the course Psychiatric/Mental Health Nursing.
View Article and Find Full Text PDFExit from the cell cycle is essential for cells to initiate a terminal differentiation program during development, but what controls this transition is incompletely understood. In this paper, we demonstrate a regulatory link between mitochondrial fission activity and cell cycle exit in follicle cell layer development during Drosophila melanogaster oogenesis. Posterior-localized clonal cells in the follicle cell layer of developing ovarioles with down-regulated expression of the major mitochondrial fission protein DRP1 had mitochondrial elements extensively fused instead of being dispersed.
View Article and Find Full Text PDFThe nuclear pore complex (NPC) mediates the transport of macromolecules between the nucleus and cytoplasm. Recent evidence indicates that structural nucleoporins, the building blocks of the NPC, have a variety of unanticipated cellular functions. Here, we report an unexpected tissue-specific requirement for the structural nucleoporin Seh1 during Drosophila oogenesis.
View Article and Find Full Text PDFDevelopment of a fertilized egg into an adult human requires trillions of cell divisions, the vast majority of which duplicate their genome once and only once. Nevertheless, trophoblast giant cells and megakaryocytes in mammals circumvent this rule by duplicating their genome multiple times without undergoing cell division, a process generally referred to as 'endoreduplication'. In contrast, arthropods such as Drosophila endoreduplicate their genome in most larval tissues, as well as in many adult tissues.
View Article and Find Full Text PDFThe proper execution of premeiotic S phase is essential to both the maintenance of genomic integrity and accurate chromosome segregation during the meiotic divisions. However, the regulation of premeiotic S phase remains poorly defined in metazoa. Here, we identify the p21(Cip1)/p27(Kip1)/p57(Kip2)-like cyclin-dependent kinase inhibitor (CKI) Dacapo (Dap) as a key regulator of premeiotic S phase and genomic stability during Drosophila oogenesis.
View Article and Find Full Text PDF