Browse
Submit Data
Databases
API
Help

Dataset Information

23 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Contributions of Costal 2-Fused interactions to Hedgehog signaling in Drosophila.

ABSTRACT: The Drosophila kinesin-family protein Costal 2 (Cos2) and its mammalian ortholog Kif7 play dual roles in Hedgehog (Hh) signaling. In the absence of Hh, Cos2 and Kif7 contribute to proteolytic processing and silencing of the Hh-regulated transcription factors, Drosophila Cubitus interruptus (Ci) and mammalian Gli proteins. Cos2 and Kif7 are also necessary for full activation of full-length Ci-155 and Gli transcription factors in response to Hh proteins. Here, we use classical fused alleles and transgenic Cos2 products deficient for Fused (Fu) association to show that Cos2 must bind to Fu to support efficient Ci-155 processing. Residual Ci-155 processing in the absence of Cos2-Fu interaction did not require Suppressor of Fused, which has been implicated in processing mammalian Gli proteins. We also provide evidence that Cos2 binding to the CORD domain of Ci-155 contributes to both Ci-155 processing and Ci-155 silencing in the absence of Hh. In the presence of Hh, Ci-155 processing is blocked and Cos2 now promotes activation of Ci-155, which requires Fu kinase activity. Here, we show that normal Ci-155 activation by Hh requires Cos2 binding to Fu, supporting the hypothesis that Cos2 mediates the apposition of Fu molecules suitable for cross-phosphorylation and consequent full activation of Fu kinase. We also find that phosphorylation of Cos2 by Fu at two previously mapped sites, S572 and S931, which is thought to mediate Ci-155 activation, is not required for normal activation of Ci-155 by Hh or by activated Fu.

SUBMITTER: Zadorozny EV

PROVIDER: S-EPMC4352975 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Costal 2 interactions with Cubitus interruptus (Ci) underlying Hedgehog-regulated Ci processing.

Project description:Extracellular Hedgehog (Hh) proteins alter cellular behaviours from flies to man by regulating the activities of Gli/Ci family transcription factors. A major component of this response in Drosophila is the inhibition of proteolytic processing of the latent transcriptional activator Ci-155 to a shorter Ci-75 repressor form. Processing is thought to rely on binding of the kinesin-family protein Cos2 directly to Ci-155 domains known as CDN and CORD, allowing Cos2-associated protein kinases to phosphorylate Ci-155 efficiently and create a binding site for an E3 ubiquitin ligase complex. Here we show that the last three zinc fingers of Ci-155 also bind Cos2 in vitro and that the zinc finger region, rather than the CDN domain, functions redundantly with the CORD domain to promote Hh-regulated Ci-155 proteolysis in wing discs. We also find evidence for a unique function of Cos2 binding to CORD. Cos2 binding to CORD, but not to other regions of Ci, is potentiated by nucleotides and abrogated by the nucleotide binding variant Cos2 S182N. Removal of the CORD region alone enhances processing under a variety of conditions. Most strikingly, CORD region deletion allows Cos2 S182N to stimulate efficient Ci processing. We deduce that the CORD region has a second function distinct from Cos2 binding that inhibits Ci processing, and that Cos2 binding to CORD relieves this inhibition. We suggest that this regulatory activity of Cos2 depends on a specific nucleotide-bound conformation that may be regulated by Hh.

| S-EPMC2996228 | biostudies-literature

Hedgehog signaling downregulates suppressor of fused through the HIB/SPOP-Crn axis in Drosophila.

Project description:Hedgehog (Hh) signaling plays vital roles in animal development and tissue homeostasis, and its misregulation causes congenital diseases and several types of cancer. Suppressor of Fused (Su(fu)) is a conserved inhibitory component of the Hh signaling pathway, but how it is regulated remains poorly understood. Here we demonstrate that in Drosophila Hh signaling promotes downregulation of Su(fu) through its target protein HIB (Hh-induced BTB protein). Interestingly, although HIB-mediated downregulation of Su(fu) depends on the E3 ubiquitin ligase Cul3, HIB does not directly regulate Su(fu) protein stability. Through an RNAi-based candidate gene screen, we identify the spliceosome factor Crooked neck (Crn) as a regulator of Su(fu) level. Epistasis analysis indicates that HIB downregulates Su(fu) through Crn. Furthermore, we provide evidence that HIB retains Crn in the nucleus, leading to reduced Su(fu) protein level. Finally, we show that SPOP, the mammalian homologue of HIB, can substitute HIB to downregulate Su(fu) level in Drosophila. Our study suggests that Hh regulates both Ci and Su(fu) levels through its target HIB, thus uncovering a novel feedback mechanism that regulates Hh signal transduction. The dual function of HIB may provide a buffering mechanism to fine-tune Hh pathway activity.

| S-EPMC4011344 | biostudies-literature

Regulation of mammalian Gli proteins by Costal 2 and PKA in Drosophila reveals Hedgehog pathway conservation.

Project description:Hedgehog (Hh) signaling activates full-length Ci/Gli family transcription factors and prevents Ci/Gli proteolytic processing to repressor forms. In the absence of Hh, Ci/Gli processing is initiated by direct Pka phosphorylation. Despite those fundamental similarities between Drosophila and mammalian Hh pathways, the differential reliance on cilia and some key signal transduction components had suggested a major divergence in the mechanisms that regulate Ci/Gli protein activities, including the role of the kinesin-family protein Costal 2 (Cos2), which directs Ci processing in Drosophila. Here, we show that Cos2 binds to three regions of Gli1, just as for Ci, and that Cos2 functions to silence mammalian Gli1 in Drosophila in a Hh-regulated manner. Cos2 and the mammalian kinesin Kif7 can also direct Gli3 and Ci processing in fly, underscoring a fundamental conserved role for Cos2 family proteins in Hh signaling. We also show that direct PKA phosphorylation regulates the activity, rather than the proteolysis of Gli in Drosophilia, and we provide evidence for an analogous action of PKA on Ci.

| S-EPMC3100709 | biostudies-literature

Tumor-Derived Suppressor of Fused Mutations Reveal Hedgehog Pathway Interactions.

Project description:The Hedgehog pathway is a potent regulator of cellular growth and plays a central role in the development of many cancers including basal cell carcinoma (BCC). The majority of BCCs arise from mutations in the Patched receptor resulting in constitutive activation of the Hedgehog pathway. Secondary driver mutations promote BCC oncogenesis and occur frequently due to the high mutational burden resulting from sun exposure of the skin. Here, we uncover novel secondary mutations in Suppressor of Fused (SUFU), the major negative regulator of the Hedgehog pathway. SUFU normally binds to a Hedgehog transcriptional activator, GLI1, in order to prevent it from initiating transcription of Hedgehog target genes. We sequenced tumor-normal pairs from patients with early sporadic BCCs. This resulted in the discovery of nine mutations in SUFU, which were functionally investigated to determine whether they help drive BCC formation. Our results show that four of the SUFU mutations inappropriately activate the Hedgehog pathway, suggesting they may act as driver mutations for BCC development. Indeed, all four of the loss of function SUFU variants were found to disrupt its binding to GLI, leading to constitutive pathway activation. Our results from functional characterization of these mutations shed light on SUFU's role in Hedgehog signaling, tumor progression, and highlight a way in which BCCs can arise.

| S-EPMC5193403 | biostudies-literature

Phosphorylation of Ci/Gli by Fused Family Kinases Promotes Hedgehog Signaling.

Project description:Hedgehog (Hh) signaling culminates in the conversion of the latent transcription factor Cubitus interruptus (Ci)/Gli into its activator form (CiA/GliA), but the underlying mechanism remains poorly understood. Here, we demonstrate that Hh stimulates the phosphorylation of Ci by the Ser/Thr kinase Fused (Fu) and that Fu-mediated phosphorylation of Ci promotes its activation. We find that Fu directly phosphorylates Ci on Ser218 and Ser1230, which primes its further phosphorylation by CK1 on adjacent sties. These phosphorylation events alter Ci binding to the pathway inhibitor Suppressor of fused (Sufu) and facilitate the recruitment of Transportion and the transcriptional coactivator CBP. Furthermore, we provide evidence that Sonic hedgehog (Shh) activates Gli2 by stimulating its phosphorylation on conserved sites through the Fu-family kinases ULK3 and mFu/STK36 in a manner depending on Gli2 ciliary localization. Hence, Fu-family kinase-mediated phosphorylation of Ci/Gli serves as a conserved mechanism that activates the Hh pathway transcription factor.

| S-EPMC6736714 | biostudies-literature

dachshund Potentiates Hedgehog Signaling during Drosophila Retinogenesis.

Project description:Proper organ patterning depends on a tight coordination between cell proliferation and differentiation. The patterning of Drosophila retina occurs both very fast and with high precision. This process is driven by the dynamic changes in signaling activity of the conserved Hedgehog (Hh) pathway, which coordinates cell fate determination, cell cycle and tissue morphogenesis. Here we show that during Drosophila retinogenesis, the retinal determination gene dachshund (dac) is not only a target of the Hh signaling pathway, but is also a modulator of its activity. Using developmental genetics techniques, we demonstrate that dac enhances Hh signaling by promoting the accumulation of the Gli transcription factor Cubitus interruptus (Ci) parallel to or downstream of fused. In the absence of dac, all Hh-mediated events associated to the morphogenetic furrow are delayed. One of the consequences is that, posterior to the furrow, dac- cells cannot activate a Roadkill-Cullin3 negative feedback loop that attenuates Hh signaling and which is necessary for retinal cells to continue normal differentiation. Therefore, dac is part of an essential positive feedback loop in the Hh pathway, guaranteeing the speed and the accuracy of Drosophila retinogenesis.

| S-EPMC4956209 | biostudies-literature

Protein phosphatase 4 promotes Hedgehog signaling through dephosphorylation of Suppressor of fused.

Project description:Reversible phosphorylation of Suppressor of fused (Sufu) is essential for Sonic Hedgehog (Shh) signal transduction. Sufu is stabilized under dual phosphorylation of protein kinase A (PKA) and glycogen synthase kinase 3β (GSK3β). Its phosphorylation is reduced with the activation of Shh signaling. However, the phosphatase in this reversible phosphorylation has not been found. Taking advantage of a proteomic approach, we identified Protein phosphatase 4 regulatory subunit 2 (Ppp4r2), an interacting protein of Sufu. Shh signaling promotes the interaction of these two proteins in the nucleus, and Ppp4 also promotes dephosphorylation of Sufu, leading to its degradation and enhancing the Gli1 transcriptional activity. Finally, Ppp4-mediated dephosphorylation of Sufu promotes proliferation of medulloblastoma tumor cells, and expression of Ppp4 is positively correlated with up-regulation of Shh pathway target genes in the Shh-subtype medulloblastoma, underscoring the important role of this regulation in Shh signaling.

| S-EPMC7442787 | biostudies-literature

Regulated delivery controls Drosophila Hedgehog, Wingless, and Decapentaplegic signaling.

Project description:Morphogen signaling proteins disperse across tissues to activate signal transduction in target cells. We investigated dispersion of Hedgehog (Hh), Wnt homolog Wingless (Wg), and Bone morphogenic protein homolog Decapentaplegic (Dpp) in the Drosophila wing imaginal disc. We discovered that delivery of Hh, Wg, and Dpp to their respective targets is regulated. We found that <5% of Hh and <25% of Wg are taken up by disc cells and activate signaling. The amount of morphogen that is taken up and initiates signaling did not change when the level of morphogen expression was varied between 50 and 200% (Hh) or 50 and 350% (Wg). Similar properties were observed for Dpp. We analyzed an area of 150 μm×150 μm that includes Hh-responding cells of the disc as well as overlying tracheal cells and myoblasts that are also activated by disc-produced Hh. We found that the extent of signaling in the disc was unaffected by the presence or absence of the tracheal and myoblast cells, suggesting that the mechanism that disperses Hh specifies its destinations to particular cells, and that target cells do not take up Hh from a common pool.

| S-EPMC8376250 | biostudies-literature

A possible role of mouse Fused (STK36) in Hedgehog signaling and Gli transcription factor regulation.

Project description:The segment polarity gene Fused (Fu) encodes a putative serine-threonine kinase Fu, which has been shown to play a key role in the Hedgehog signaling pathway of Drosophila. Human FU (hFU) has been shown to enhance the activity of Gli transcription factors, targets of the signaling pathway. However, Fu ( -/- ) mice do not show aberrant embryonic development indicating that mouse Fu (mFu) is dispensable for Hedgehog signaling until birth. In order to investigate if there are important differences between hFU and mFu, we cloned the cDNA, analyzed expression and tested the ability of mFu to regulate Gli proteins. Of the tested tissues only brain and testis showed significant expression. However, in transient overexpression analyses mFu was able to enhance Gli induced transcription in a manner similar to hFU. Thus, we turned to RNAi in order to test if mFu would be important for Hedgehog signaling after all. In one cell line with reduced mFu expression the Hedgehog signaling was severely hampered, indicating that mFu may have a role in Hedgehog signaling and Gli regulation in some cellular situations.

| S-EPMC2443232 | biostudies-other

Suppressor of Fused Chaperones Gli Proteins To Generate Transcriptional Responses to Sonic Hedgehog Signaling.

Project description:Cellular responses to the graded Sonic Hedgehog (Shh) morphogenic signal are orchestrated by three Gli genes that give rise to both transcription activators and repressors. An essential downstream regulator of the pathway, encoded by the tumor suppressor gene Suppressor of fused (Sufu), plays critical roles in the production, trafficking, and function of Gli proteins, but the mechanism remains controversial. Here, we show that Sufu is upregulated in active Shh responding tissues and accompanies Gli activators translocating into and Gli repressors out of the nucleus. Trafficking of Sufu to the primary cilium, potentiated by Gli activators but not repressors, was found to be coupled to its nuclear import. We have identified a nuclear export signal (NES) motif of Sufu in juxtaposition to the protein kinase A (PKA) and glycogen synthase kinase 3 (GSK3) dual phosphorylation sites and show that Sufu binds the chromatin with both Gli1 and Gli3. Close comparison of neural tube development among individual Ptch1-/-, Sufu-/-, and Ptch1-/-; Sufu-/- double mutant embryos indicates that Sufu is critical for the maximal activation of Shh signaling essential to the specification of the most-ventral neurons. These data define Sufu as a novel class of molecular chaperone required for every aspect of Gli regulation and function.

| S-EPMC5247608 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data