Gap1

..This response for pb implicates at least two signal transduction pathways, those involving Ras1 and Notch...

..Further, lethal insertions in replication factor complex 4 (rfc4) and GTPase-activating protein 1 (Gap1) exhibit specific mitotic chromosome defects, discovering previously unknown roles for these proteins in chromosome ..

..Its human ortholog, Fbw7, is commonly lost in cancers, suggesting that failure to degrade ago/Fbw7 targets drives excess tissue growth...

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..Ras activity is negatively regulated by GTPase activating proteins (GAPs). It has been proposed that RasGAP may also function as an effector of Ras activity...

..Here we report the structural requirements for Gap1 activity in cone cell fate decisions during Drosophila eye development...

..These receptor tyrosine kinase-mediated pathways may share not only intracellular signaling components but also extracellular factors that modulate the strength of the signal...

..Sprouty binds to two intracellular components of the Ras pathway, Drk and Gap1. Our results indicate that Sprouty is a widespread inhibitor of Ras pathway signal transduction.

..development reveal strong genetic interactions with genes of the Ras signalling pathway (torpedo, vein, veinlet and Gap), blistered, plexus and net, in both adult wing phenotypes and cell behaviour in genetic mosaics...

..These findings define a novel mechanism by which growth factor signaling directly inactivates a critical component of the intrinsic cell death machinery. These studies provide further insights into the function of ras as an oncogene...

..Thus nested expression of vnd and the DER activator rhomboid is crucial to subdivide the neuroectoderm into the three dorsoventral domains...

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..Finally, using different UAS-FLP, GAL4 and existing FRT lines, we have built stocks that permit the analysis of approximately 95% of the genome in follicular mosaics...

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..We conclude that Ebi has two distinct functions; it promotes the degradation of a repressor of neuronal differentiation (Ttk88), and has a second independent function that limits S phase entry...

..In addition, Egfr activity has to be repressed through the activity of D-cbl to ensure the absence of signaling in the ventral most follicle cells...

..Analysis of the function of dof, which encodes a cytoplasmic protein required for FGF signal transduction may provide an insight into these issues...

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..simulans...

..These data reveal functional attributes of the Cdk8 module, apart from its regulated kinase activity, that may contribute to the diversification of genetic programs...

..a large and highly conserved protein whose only known function is to serve as a GTPase-Activating Protein (GAP) for Ras...

..rbf1 mutant cells is suppressed by the activation of DER, ras, or raf or by the inactivation of argos, sprouty, or gap1, and inhibition of DER strongly enhances apoptosis in rbf1 mutant discs...

..Finally, despite the relatively large size of the PP2C gene family in metazoans, this study represents only the second genetic characterization of a PP2C in these organisms...

..Our results indicate that IAP gene family members may have acquired other functions, such as the regulation of the tumour necrosis factor-like IMD pathway during innate immune responses...

..Thus, fred acts in close concert with the Notch signaling pathway. Dosage-sensitive genetic interaction also suggests a close relationship between fred and ed...

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..We have also studied the role of the poxn gene in the inhibition of bract induction in chemosensory bristles...

..Together, our results support a model whereby ED defines an independent pathway that antagonizes EGFR signaling by regulating the activity, but not the level, of the TTK88 transcriptional repressor...

..We propose that binding to 14-3-3 by Raf is necessary but not sufficient for the activation of Raf and that overexpressed Drosophila 14-3-3 requires Ras1 to activate D-Raf...

..The protein structure is consistent with its participation in cell-cell interaction during eye development...

..In addition to molecules previously identified from vertebrate studies, i.e. Grb2, Sos, Ras-Gap, p21ras, Raf, MEK and MAPK, genetic studies have suggested that two novel proteins, the protein tyrosine ..

..Based on the genetic interactions with Sos, we suggest that Star also has a later role in photoreceptor development including the recruitment of the R7 cell through the sevenless pathway...

..phyl is also required for embryonic nervous system and sensory bristle development...

..This pathway involves a membrane-bound receptor tyrosine kinase (RTK) that is similar to other Drosophila RTKs, such as sevenless, and the mammalian RTKs, such as the epidermal growth factor or platelet-derived growth factor receptors...

..These data suggest that photoreceptors other than R7 use a Ras1 signalling pathway activated by the spitz/Egfr interaction, in a manner analogous to the Ras1 pathway activated by boss/sevenless in photoreceptor R7...

..Thus the Ras/Raf pathway also appears to be essential for G-protein-coupled neurotransmission...

..Ras and the Mapk pathway are also needed for Egf-regulated cell division/survival, but Pointed is dispensable...

..Our study provides in vivo evidence that Raf can be activated by an RTK in a Ras-independent pathway...

..Thus the determination of cells by the DER pathway is regulated by a balance between extracellular activating and inhibiting signals. This is the first in vivo example of an extracellular inhibitor of a receptor tyrosine kinase...

..Using this technique, we have identified a new mutant, mip (more inner photoreceptors), in which this map shows a striking hyperinnervation...

Mutations in a gene called sextra (sxt) have been isolated...

..Inactivation of the locus, Gap1, mimics constitutive activation of the Sevenless receptor tyrosine kinase and eliminates the need for a functional ..

..Our data suggest that yan functions as a cell-autonomous negative regulator of photoreceptor development; in the presumptive R7 and cone cells, yan appears to act antagonistically to the proneural signal mediated by sevenless and Ras1...

..The more inner photoreceptors mutation, an allele of gap1, results in the differentiation of excess R7s in the eye, whose axons invade ..

..In contrast to the receptor and its ligand, these components are shared between different signal transduction pathways not only in Drosophila but are also homologous to components involved in signal transduction in other organisms...

..boss reporter gene in multiple cells assessed for homozygous mutant phenotypes, insertions in the marbles, glass, gap1, and fasciclin II genes were isolated...

..Two identified interacting genes were the proto-oncogene Ras1 and its functional antagonist Gap1, prominent intermediaries in known signal transduction pathways...

..NF1 appears to regulate the rutabaga-encoded adenylyl cyclase rather than the Ras-Raf pathway. Moreover, the NF1 defect was rescued by the exposure of cells to pharmacological treatment that increased concentrations of cAMP...

..Thus, NF1 and PKA appear to interact in a pathway that controls the overall growth of Drosophila...

..Three of these argos-expressing cells differentiate into the three remaining COPs and they prevent neighboring cells from becoming extra COPs...

..Thus, biologically relevant phenotypes and genetic interactions are identified using this method. The screen is a powerful new tool for developmental genetics; similar approaches can also be developed for other organisms...

..Current work in both systems has provided new opportunities to investigate the potential for the cross-talk between these different signaling pathways...

..The cell division defects found in dally mutants implicate the Glypican group of integral membrane proteoglycans in the control of cell division during development...

..The Ras cascade functions in other Drosophila signal transduction pathways, eliciting a distinct response in each case, presumably through phosphorylation of specific transcription factors...

..Our results also suggest that seven-up controls decisions not only between photoreceptor subtypes, but also between neuronal and non-neuronal fates...

..Specifically, we show that the Gap1 gene, which encodes a Drosophila homologue of mammalian GTPase-activating protein, is required in somatic follicle ..

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..From the perspective of learning theory, this can be viewed as a savings experiment...

..Recent genetic and molecular studies have provided important clues regarding the nature of the molecules involved in cellular signalling and neuronal differentiation...

..Pokkuri-mediated repression represents one such regulatory mechanism. The positive and negative signaling pathways operating in the fate determination of other photoreceptor cells are also discussed...

..The proposed research aims to begin filling this basic gap in our understanding of Drosophila females...

..These approaches could eventually be used in human populations. ..