Dataset Information

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

ABSTRACT: 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.

SUBMITTER: Liu C

PROVIDER: S-EPMC4011344 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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

Liu Chen C Zhou Zizhang Z Yao Xia X Chen Ping P Sun Man M Su Miya M Chang Cunjie C Yan Jun J Jiang Jin J Zhang Qing Q

Cell research 20140307 5

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 downregul ...[more]

PMID: 24603360

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Project description:Cilia assembly, maintenance and the localization of signal-transduction proteins necessitate a functioning intraflagellar transport (IFT). The IFT machinery moves cargo along a microtubule scaffold from the proximal to the distal end of the cilium. This anterograde transport is facilitated by a large multiprotein complex IFT-B, which consists of 16 proteins in total and recruits motor protein Kinesin-2 for active movement. TTC30A and TTC30B are integral components of this complex and were shown before to have redundant function in context of IFT. One paralogue could compensate the loss of the other, preventing the disruption of IFT-B and thus a severe ciliogenesis defect with no formation of the cilium. Affinity-based protein complex analysis of endogenously tagged cells, generated via CRISPR/Cas9 system as described before, revealed paralogue specific protein interactors proposing the involvement of TTC30A or TTC30B in other ciliary functions, particularly Sonic hedgehog signaling (Shh). Defects in this ciliary signaling pathway are often correlated to synpolydactyly, which intriguingly is also linked to a rare TTC30 variant. In this study we focus on the so far unknown interaction of TTC30A with protein kinase A catalytic subunit α PRKACA, which is a negative regulator of Shh pathway. For an in-depth analysis of this unique interaction and the influence on Shh, we used previously, via the CRISPR/Cas9 system, generated TTC30A or B single- and double-knockout hTERT-RPE1 cells as well as rescue cells harboring the TTC30 mutation. Our systematic approach revealed the paralogue specific influence of TTC30A KO and mutated TTC30A on the activity of PRKACA as well as the uptake of Smoothened into the cilium resulting in a downregulation of Sonic hedgehog signaling. Affinity-based protein complex analysis of wildtype versus mutated TTC30A or TTC30B uncovered differences in interaction pattern. These interactome alterations combined with Shh downregulation suggest a possible mechanism of how mutant TTC30A and respectively TTC30A KO are linked to synpolydactyly.

Dataset Information

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

Publications

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

Similar Datasets

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