Biomaterial Database

Spargel/dPGC-1 is a new downstream effector in the insulin-TOR signaling pathway in Drosophila. 2013

Subhas Mukherjee, and Atanu Duttaroy

Department of Biology, Howard University, Washington, DC 20059.

Insulin and target of rapamycin (TOR) signaling pathways converge to maintain growth so a proportionate body form is attained. Insufficiency in either insulin or TOR results in developmental growth defects due to low ATP level. Spargel is the Drosophila homolog of PGC-1, which is an omnipotent transcriptional coactivator in mammals. Like its mammalian counterpart, Spargel/dPGC-1 is recognized for its role in energy metabolism through mitochondrial biogenesis. An earlier study demonstrated that Spargel/dPGC-1 is involved in the insulin-TOR signaling, but a comprehensive analysis is needed to understand exactly which step of this pathway Spargel/PGC-1 is essential. Using genetic epistasis analysis, we demonstrated that a Spargel gain of function can overcome the TOR and S6K mediated cell size and cell growth defects in a cell autonomous manner. Moreover, the tissue-restricted phenotypes of TOR and S6k mutants are rescued by Spargel overexpression. We have further elucidated that Spargel gain of function sets back the mitochondrial numbers in growth-limited TOR mutant cell clones, which suggests a possible mechanism for Spargel action on cells and tissue to attain normal size. Finally, excess Spargel can ameliorate the negative effect of FoxO overexpression only to a limited extent, which suggests that Spargel does not share all of the FoxO functions and consequently cannot significantly rescue the FoxO phenotypes. Together, our observation established that Spargel/dPGC-1 is indeed a terminal effector in the insulin-TOR pathway operating below TOR, S6K, Tsc, and FoxO. This led us to conclude that Spargel should be incorporated as a new member of this growth-signaling pathway.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D004331	Drosophila melanogaster	A species of fruit fly frequently used in genetics because of the large size of its chromosomes.	D. melanogaster,Drosophila melanogasters,melanogaster, Drosophila
D004843	Epistasis, Genetic	A form of gene interaction whereby the expression of one gene interferes with or masks the expression of a different gene or genes. Genes whose expression interferes with or masks the effects of other genes are said to be epistatic to the effected genes. Genes whose expression is affected (blocked or masked) are hypostatic to the interfering genes.	Deviation, Epistatic,Epistatic Deviation,Genes, Epistatic,Genes, Hypostatic,Epistases, Genetic,Gene-Gene Interaction, Epistatic,Gene-Gene Interactions, Epistatic,Genetic Epistases,Genetic Epistasis,Interaction Deviation,Non-Allelic Gene Interactions,Epistatic Gene,Epistatic Gene-Gene Interaction,Epistatic Gene-Gene Interactions,Epistatic Genes,Gene Gene Interaction, Epistatic,Gene Gene Interactions, Epistatic,Gene Interaction, Non-Allelic,Gene Interactions, Non-Allelic,Gene, Epistatic,Gene, Hypostatic,Hypostatic Gene,Hypostatic Genes,Interaction, Epistatic Gene-Gene,Interaction, Non-Allelic Gene,Interactions, Epistatic Gene-Gene,Interactions, Non-Allelic Gene,Non Allelic Gene Interactions,Non-Allelic Gene Interaction
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D042925	Positive Transcriptional Elongation Factor B	A transcriptional elongation factor complex that is comprised of a heterodimer of CYCLIN-DEPENDENT KINASE 9 and one of several CYCLINS including TYPE T CYCLINS and cyclin K. It functions by phosphorylating the carboxy-terminal domain of RNA POLYMERASE II.	P-TEFb,Positive Transcription Elongation Factor B,tat-Associated Kinase,tat Associated Kinase
D051858	Forkhead Transcription Factors	A subclass of winged helix DNA-binding proteins that share homology with their founding member fork head protein, Drosophila.	Forkhead Box Protein,Forkhead Box Transcription Factor,Forkhead Protein,Forkhead Transcription Factor,Forkhead Box Proteins,Forkhead Box Transcription Factors,Forkhead Proteins,Fox Transcription Factors,Box Protein, Forkhead,Box Proteins, Forkhead,Factor, Forkhead Transcription,Protein, Forkhead,Protein, Forkhead Box,Proteins, Forkhead Box,Transcription Factor, Forkhead,Transcription Factors, Forkhead,Transcription Factors, Fox
D058570	TOR Serine-Threonine Kinases	A serine threonine kinase that controls a wide range of growth-related cellular processes. The protein is referred to as the target of RAPAMYCIN due to the discovery that SIROLIMUS (commonly known as rapamycin) forms an inhibitory complex with TACROLIMUS BINDING PROTEIN 1A that blocks the action of its enzymatic activity.	TOR Kinase,TOR Kinases,TOR Serine-Threonine Kinase,Target of Rapamycin Protein,mTOR Serine-Threonine Kinase,mTOR Serine-Threonine Kinases,FK506 Binding Protein 12-Rapamycin Associated Protein 1,FKBP12-Rapamycin Associated Protein,FKBP12-Rapamycin Complex-Associated Protein,Mammalian Target of Rapamycin,Mechanistic Target of Rapamycin Protein,RAFT-1 Protein,Rapamycin Target Protein,Target of Rapamycin Proteins,mTOR Protein,FK506 Binding Protein 12 Rapamycin Associated Protein 1,FKBP12 Rapamycin Associated Protein,FKBP12 Rapamycin Complex Associated Protein,Kinase, TOR,Kinase, TOR Serine-Threonine,Kinase, mTOR Serine-Threonine,Kinases, TOR Serine-Threonine,Kinases, mTOR Serine-Threonine,Protein Target, Rapamycin,Protein, RAFT-1,Protein, mTOR,RAFT 1 Protein,Rapamycin Protein Target,Serine-Threonine Kinase, TOR,Serine-Threonine Kinase, mTOR,Serine-Threonine Kinases, TOR,Serine-Threonine Kinases, mTOR,TOR Serine Threonine Kinase,TOR Serine Threonine Kinases,mTOR Serine Threonine Kinase,mTOR Serine Threonine Kinases
D019521	Body Patterning	The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.	Axial Patterning (Embryology),Embryonic Pattern Formation,Polarity of Development,Body Pattern Formation,Body Pattern Specification,Embryonic Pattern Specification,Development Polarity,Embryonic Pattern Formations,Formation, Embryonic Pattern,Pattern Formation, Body,Pattern Formation, Embryonic,Pattern Specification, Body,Pattern Specification, Embryonic,Patterning, Axial (Embryology),Patterning, Body,Specification, Body Pattern,Specification, Embryonic Pattern