scholarly journals LUZP1, a novel regulator of primary cilia and the actin cytoskeleton, is a contributing factor in Townes-Brocks Syndrome

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Laura Bozal-Basterra ◽  
María Gonzalez-Santamarta ◽  
Veronica Muratore ◽  
Aitor Bermejo-Arteagabeitia ◽  
Carolina Da Fonseca ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Leucine Zipper ◽  
Human Fibroblasts ◽  
Sonic Hedgehog Signaling ◽  
Cilia Formation ◽  
Ubiquitin Proteasome ◽  
And Function ◽  
Leucine Zipper Protein

Primary cilia are sensory organelles crucial for cell signaling during development and organ homeostasis. Cilia arise from centrosomes and their formation and function is governed by numerous factors. Through our studies on Townes-Brocks Syndrome (TBS), a rare disease linked to abnormal cilia formation in human fibroblasts, we uncovered the leucine-zipper protein LUZP1 as an interactor of truncated SALL1, a dominantly-acting protein causing the disease. Using TurboID proximity labeling and pulldowns, we show that LUZP1 associates with factors linked to centrosome and actin filaments. Here, we show that LUZP1 is a cilia regulator. It localizes around the centrioles and to actin cytoskeleton. Loss of LUZP1 reduces F-actin levels, facilitates ciliogenesis and alters Sonic Hedgehog signaling, pointing to a key role in cytoskeleton-cilia interdependency. Truncated SALL1 increases the ubiquitin proteasome-mediated degradation of LUZP1. Together with other factors, alterations in LUZP1 may be contributing to TBS etiology.

scholarly journals LUZP1, a novel regulator of primary cilia and the actin cytoskeleton, is altered in Townes-Brocks Syndrome

2019 ◽  
Author(s):  
Laura Bozal-Basterra ◽  
María Gonzalez-Santamarta ◽  
Aitor Bermejo-Arteagabeitia ◽  
Carolina Da Fonseca ◽  
Olatz Pampliega ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Leucine Zipper ◽  
Truncated Form ◽  
Sonic Hedgehog Signaling ◽  
Pericentriolar Material ◽  
Ubiquitin Proteasome ◽  
Leucine Zipper Protein

ABSTRACTPrimary cilia are sensory organelles that are crucial for cell signaling during development and organ homeostasis. Cilia arise from the centrosome and their formation is governed by numerous regulatory factors. We show that the leucine-zipper protein LUZP1 localizes to the pericentriolar material and actin cytoskeleton. Using TurboID proximity labeling and pulldowns, LUZP1 associates with factors linked to centrosome and actin filaments. Loss of LUZP1 reduces F-actin levels, facilitating ciliogenesis and altering Sonic Hedgehog signaling, pointing to a key role in the cytoskeleton-cilia interdependency. Moreover, we show that LUZP1 interacts with a truncated form of the transcription factor SALL1 that causes Townes-Brocks Syndrome. TBS is characterized by digit, heart and kidney malformations and is linked in part to defective cilia. Truncated SALL1 increases the ubiquitin proteasome-mediated degradation of LUZP1. Alteration of LUZP1 levels may be a contributing factor to TBS, suggesting possible therapies using modulators of cilia and cytoskeletal function.

scholarly journals NRF2-dependent gene expression promotes ciliogenesis and Hedgehog signaling

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ana Martin-Hurtado ◽  
Raquel Martin-Morales ◽  
Natalia Robledinos-Antón ◽  
Ruth Blanco ◽  
Ines Palacios-Blanco ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Embryonic Stem ◽  
Mtor Inhibitors ◽  
Gene Promoters ◽  
Protein Levels ◽  
Functional Connections ◽  
Differentiated Cells ◽  
Cilia Formation ◽  
And Function

Abstract The transcription factor NRF2 is a master regulator of cellular antioxidant and detoxification responses, but it also regulates other processes such as autophagy and pluripotency. In human embryonic stem cells (hESCs), NRF2 antagonizes neuroectoderm differentiation, which only occurs after NRF2 is repressed via a Primary Cilia-Autophagy-NRF2 (PAN) axis. However, the functional connections between NRF2 and primary cilia, microtubule-based plasma membrane protrusions that function as cellular antennae, remain poorly understood. For instance, nothing is known about whether NRF2 affects cilia, or whether cilia regulation of NRF2 extends beyond hESCs. Here, we show that NRF2 and primary cilia reciprocally regulate each other. First, we demonstrate that fibroblasts lacking primary cilia have higher NRF2 activity, which is rescued by autophagy-activating mTOR inhibitors, indicating that the PAN axis also operates in differentiated cells. Furthermore, NRF2 controls cilia formation and function. NRF2-null cells grow fewer and shorter cilia and display impaired Hedgehog signaling, a cilia-dependent pathway. These defects are not due to increased oxidative stress or ciliophagy, but rather to NRF2 promoting expression of multiple ciliogenic and Hedgehog pathway genes. Among these, we focused on GLI2 and GLI3, the transcription factors controlling Hh pathway output. Both their mRNA and protein levels are reduced in NRF2-null cells, consistent with their gene promoters containing consensus ARE sequences predicted to bind NRF2. Moreover, GLI2 and GLI3 fail to accumulate at the ciliary tip of NRF2-null cells upon Hh pathway activation. Given the importance of NRF2 and ciliary signaling in human disease, our data may have important biomedical implications.

scholarly journals ERICH3 in Primary Cilia Regulates Cilium Formation and the Localisations of Ciliary Transport and Sonic Hedgehog Signaling Proteins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mona Alsolami ◽  
Stefanie Kuhns ◽  
Manal Alsulami ◽  
Oliver E. Blacque
Keyword(s):  
Sonic Hedgehog ◽  
Primary Cilium ◽  
Molecular Motors ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Signaling Proteins ◽  
Sonic Hedgehog Signaling ◽  
And Function

Abstract Intraflagellar transport (IFT) is essential for the formation and function of the microtubule-based primary cilium, which acts as a sensory and signalling device at the cell surface. Consisting of IFT-A/B and BBSome cargo adaptors that associate with molecular motors, IFT transports protein into (anterograde IFT) and out of (retrograde IFT) the cilium. In this study, we identify the mostly uncharacterised ERICH3 protein as a component of the mammalian primary cilium. Loss of ERICH3 causes abnormally short cilia and results in the accumulation of IFT-A/B proteins at the ciliary tip, together with reduced ciliary levels of retrograde transport regulators, ARL13B, INPP5E and BBS5. We also show that ERICH3 ciliary localisations require ARL13B and BBSome components. Finally, ERICH3 loss causes positive (Smoothened) and negative (GPR161) regulators of sonic hedgehog signaling (Shh) to accumulate at abnormally high levels in the cilia of pathway-stimulated cells. Together, these findings identify ERICH3 as a novel component of the primary cilium that regulates cilium length and the ciliary levels of Shh signaling molecules. We propose that ERICH3 functions within retrograde IFT-associated pathways to remove signaling proteins from cilia.

scholarly journals The E3 ubiquitin ligase UBR5 regulates centriolar satellite stability and primary cilia

2018 ◽  
Vol 29 (13) ◽  
pp. 1542-1554 ◽  
Author(s):  
Robert F. Shearer ◽  
Kari-Anne Myrum Frikstad ◽  
Jessie McKenna ◽  
Rachael A. McCloy ◽  
Niantao Deng ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Developmental Disorders ◽  
Primary Cilia ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Interacting Protein ◽  
Robust Model ◽  
Cilia Formation ◽  
Cytoplasmic Organization ◽  
Ubiquitin Proteasome

Primary cilia are crucial for signal transduction in a variety of pathways, including hedgehog and Wnt. Disruption of primary cilia formation (ciliogenesis) is linked to numerous developmental disorders (known as ciliopathies) and diseases, including cancer. The ubiquitin–proteasome system (UPS) component UBR5 was previously identified as a putative positive regulator of ciliogenesis in a functional genomics screen. UBR5 is an E3 ubiquitin ligase that is frequently deregulated in tumors, but its biological role in cancer is largely uncharacterized, partly due to a lack of understanding of interacting proteins and pathways. We validated the effect of UBR5 depletion on primary cilia formation using a robust model of ciliogenesis, and identified CSPP1, a centrosomal and ciliary protein required for cilia formation, as a UBR5-interacting protein. We show that UBR5 ubiquitylates CSPP1, and that UBR5 is required for cytoplasmic organization of CSPP1-comprising centriolar satellites in centrosomal periphery, suggesting that UBR5-mediated ubiquitylation of CSPP1 or associated centriolar satellite constituents is one underlying requirement for cilia expression. Hence, we have established a key role for UBR5 in ciliogenesis that may have important implications in understanding cancer pathophysiology.

scholarly journals A novel role for primary cilia in airway remodeling

2017 ◽  
Vol 313 (2) ◽  
pp. L328-L338 ◽  
Author(s):  
Carol S. Trempus ◽  
Weifeng Song ◽  
Ahmed Lazrak ◽  
Zhihong Yu ◽  
Judy R. Creighton ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Calcium Influx ◽  
Airway Remodeling ◽  
Critical Role ◽  
Calcium Flux ◽  
Airway Smooth Muscle Cells ◽  
Mechanical Stimuli ◽  
Sonic Hedgehog Signaling

Primary cilia (PC) are solitary cellular organelles that play critical roles in development, homeostasis, and disease pathogenesis by modulating key signaling pathways such as Sonic Hedgehog and calcium flux. The antenna-like shape of PC enables them also to facilitate sensing of extracellular and mechanical stimuli into the cell, and a critical role for PC has been described for mesenchymal cells such as chondrocytes. However, nothing is known about the role of PC in airway smooth muscle cells (ASMCs) in the context of airway remodeling. We hypothesized that PC on ASMCs mediate cell contraction and are thus integral in the remodeling process. We found that PC are expressed on ASMCs in asthmatic lungs. Using pharmacological and genetic methods, we demonstrated that PC are necessary for ASMC contraction in a collagen gel three-dimensional model both in the absence of external stimulus and in response to the extracellular component hyaluronan. Mechanistically, we demonstrate that the effect of PC on ASMC contraction is, to a small extent, due to their effect on Sonic Hedgehog signaling and, to a larger extent, due to their effect on calcium influx and membrane depolarization. In conclusion, PC are necessary for the development of airway remodeling by mediating calcium flux and Sonic Hedgehog signaling.

scholarly journals ARL13B regulates Sonic Hedgehog signaling from outside primary cilia

2019 ◽  
Author(s):  
Eduardo D. Gigante ◽  
Megan R. Taylor ◽  
Anna A. Ivanova ◽  
Richard A. Kahn ◽  
Tamara Caspary
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Protein Trafficking ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Complete Loss ◽  
Wild Type ◽  
Sonic Hedgehog Signaling ◽  
Biochemical Function

AbstractARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B’s role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.

scholarly journals Author response: ARL13B regulates Sonic hedgehog signaling from outside primary cilia

2019 ◽  
Author(s):  
Eduardo D Gigante ◽  
Megan R Taylor ◽  
Anna A Ivanova ◽  
Richard A Kahn ◽  
Tamara Caspary
Keyword(s):  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Author Response ◽  
Sonic Hedgehog Signaling

scholarly journals ARL13B regulates Sonic hedgehog signaling from outside primary cilia

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Eduardo D Gigante ◽  
Megan R Taylor ◽  
Anna A Ivanova ◽  
Richard A Kahn ◽  
Tamara Caspary
Keyword(s):  
Signal Transduction ◽  
Sonic Hedgehog ◽  
Protein Trafficking ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Complete Loss ◽  
Wild Type ◽  
Sonic Hedgehog Signaling ◽  
Biochemical Function

ARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B’s role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.

scholarly journals KIF14 controls ciliogenesis via regulation of Aurora A and is important for Hedgehog signaling

2020 ◽  
Vol 219 (6) ◽  
Author(s):  
Petra Pejskova ◽  
Madeline Louise Reilly ◽  
Lucia Bino ◽  
Ondrej Bernatik ◽  
Linda Dolanska ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Cell Cycle Progression ◽  
Primary Cilia ◽  
Aurora A ◽  
Pathway Activation ◽  
Cilia Formation ◽  
Tightly Coupled ◽  
Hh Signaling

Primary cilia play critical roles in development and disease. Their assembly and disassembly are tightly coupled to cell cycle progression. Here, we present data identifying KIF14 as a regulator of cilia formation and Hedgehog (HH) signaling. We show that RNAi depletion of KIF14 specifically leads to defects in ciliogenesis and basal body (BB) biogenesis, as its absence hampers the efficiency of primary cilium formation and the dynamics of primary cilium elongation, and disrupts the localization of the distal appendage proteins SCLT1 and FBF1 and components of the IFT-B complex. We identify deregulated Aurora A activity as a mechanism contributing to the primary cilium and BB formation defects seen after KIF14 depletion. In addition, we show that primary cilia in KIF14-depleted cells are defective in response to HH pathway activation, independently of the effects of Aurora A. In sum, our data point to KIF14 as a critical node connecting cell cycle machinery, effective ciliogenesis, and HH signaling.

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