PMID:15802506

Citation	Cygnar, KD, Gao, X, Pan, D and Neufeld, TP (2005) The phosphatase subunit tap42 functions independently of target of rapamycin to regulate cell division and survival in Drosophila. Genetics 170:733-40
Abstract	The protein phosphatase 2A (PP2A) regulatory subunit Tap42 is essential for target of rapamycin (TOR)-mediated signaling in yeast, but its role in higher eukaryotes has not been established. Here we show that Tap42 does not contribute significantly to TOR signaling in Drosophila, as disruption of the Tap42 gene does not cause defects in cell growth, metabolism, or S6-kinase activity characteristic of TOR inactivation. In addition, Tap42 is not required for increased cell growth in response to activation of TOR signaling. Instead, we find that Tap42 mutations cause disorganization of spindle microtubules in larval neuroblasts, leading to a preanaphase mitotic arrest in these cells. Loss of Tap42 ultimately results in increased JNK signaling, caspase activation, and cell death. These phenotypes are associated with increased accumulation and nuclear localization of PP2A in Tap42 mutant cells. Our results demonstrate that the role of Tap42 in TOR signaling has not been conserved in higher eukaryotes, indicating fundamental differences in the mechanisms of TOR signaling between yeast and higher eukaryotes.
Links	PubMed PMC1450424 Online version:10.1534/genetics.104.039909
Keywords	Adaptor Proteins, Signal Transducing; Amino Acid Sequence; Animals; Cell Cycle; Cell Death; Cell Division; Cell Nucleus/metabolism; Cell Proliferation; Cell Separation; Cell Survival; Conserved Sequence; Drosophila Proteins/genetics; Drosophila Proteins/metabolism; Drosophila Proteins/physiology; Drosophila melanogaster; Enzyme Activation; Flow Cytometry; Genetic Vectors; Humans; Microtubules/metabolism; Mitotic Spindle Apparatus; Models, Genetic; Molecular Sequence Data; Mutation; Neurons/metabolism; Phenotype; Phosphatidylinositol 3-Kinases/metabolism; Phosphatidylinositol 3-Kinases/physiology; Phosphoprotein Phosphatases/genetics; Phosphoprotein Phosphatases/physiology; Protein Kinases; Protein Phosphatase 2; Protein Structure, Tertiary; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins/genetics; Saccharomyces cerevisiae Proteins/physiology; Signal Transduction; Species Specificity; Transgenes
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
DROME:Q9VJZ5		GO:0007052: mitotic spindle organization	ECO:0000315:		P		Figure 3b shows that mitotic spindles are small and poorly organized in TAP 42 mutants.	complete CACAO 6653
DROME:Q9VJZ5	involved_in	GO:0007052: mitotic spindle organization	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

See Help:References for how to manage references in GONUTS.