scholarly journals LUZP1 and the tumor suppressor EPLIN modulate actin stability to restrict primary cilia formation

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
João Gonçalves ◽  
Amit Sharma ◽  
Étienne Coyaud ◽  
Estelle M.N. Laurent ◽  
Brian Raught ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Basal Body ◽  
Actin Filaments ◽  
Primary Cilia ◽  
Human Diseases ◽  
Actin Dynamics ◽  
Interacting Protein ◽  
Disease States ◽  
Cilia Formation ◽  
Cilia And Flagella

Cilia and flagella are microtubule-based cellular projections with important sensory and motility functions. Their absence or malfunction is associated with a growing number of human diseases collectively referred to as ciliopathies. However, the fundamental mechanisms underpinning cilia biogenesis and functions remain only partly understood. Here, we show that depleting LUZP1 or its interacting protein, EPLIN, increases the levels of MyosinVa at the centrosome and primary cilia formation. We further show that LUZP1 localizes to both actin filaments and the centrosome/basal body. Like EPLIN, LUZP1 is an actin-stabilizing protein that regulates actin dynamics, at least in part, by mobilizing ARP2 to the centrosomes. Both LUZP1 and EPLIN interact with known ciliogenesis and cilia-length regulators and as such represent novel players in actin-dependent centrosome to basal body conversion. Ciliogenesis deregulation caused by LUZP1 or EPLIN loss may thus contribute to the pathology of their associated disease states.

scholarly journals LUZP1 and the tumour suppressor EPLIN are negative regulators of primary cilia formation

2019 ◽  
Author(s):  
João Gonçalves ◽  
Étienne Coyaud ◽  
Estelle M.N. Laurent ◽  
Brian Raught ◽  
Laurence Pelletier
Keyword(s):  
Basal Body ◽  
Actin Filaments ◽  
Primary Cilia ◽  
Tumour Suppressor ◽  
Actin Dynamics ◽  
Negative Regulators ◽  
Interacting Protein ◽  
Associated Diseases ◽  
Cilia Formation ◽  
Dependent Processes

ABSTRACTCilia/flagella are microtubule-based cellular projections with important sensory and motility functions. Their absence or malfunction is associated with a growing number of human diseases collectively referred to as ciliopathies. However, the fundamental mechanisms underpinning cilia biogenesis and functions remain only partly understood. Here, we show that LUZP1, and its interacting protein EPLIN, are negative regulators of primary cilia formation. LUZP1 is an actin-associated protein that localizes to both actin filaments and the centrosome/basal body. Like EPLIN, LUZP1 is an actin-stabilizing protein and likely regulates actin dynamics at the centrosome. Both proteins interact with ciliogenesis and cilia length regulators, and are potential players in the actin-dependent processes involved in centrosome to basal body conversion. Ciliogenesis deregulation caused by LUZP1 or EPLIN loss may contribute to the pathology of their associated diseases.SUMMARYGonçalves et al. show that LUZP1 and its interactor EPLIN are negative regulators of ciliogenesis. LUZP1 is a novel actin-stabilizing protein localizing at the centrosome and basal body where it may regulate actin-associated processes.

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 Drosophila Bld10 Is a Centriolar Protein That Regulates Centriole, Basal Body, and Motile Cilium Assembly

2009 ◽  
Vol 20 (10) ◽  
pp. 2605-2614 ◽  
Author(s):  
Violaine Mottier-Pavie ◽  
Timothy L. Megraw
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Basal Body ◽  
Human Diseases ◽  
Cell Physiology ◽  
Basal Bodies ◽  
Male Sterile ◽  
Central Pair ◽  
Animal Development ◽  
Cilia And Flagella

Cilia and flagella play multiple essential roles in animal development and cell physiology. Defective cilium assembly or motility represents the etiological basis for a growing number of human diseases. Therefore, how cilia and flagella assemble and the processes that drive motility are essential for understanding these diseases. Here we show that Drosophila Bld10, the ortholog of Chlamydomonas reinhardtii Bld10p and human Cep135, is a ubiquitous centriolar protein that also localizes to the spermatid basal body. Mutants that lack Bld10 assemble centrioles and form functional centrosomes, but centrioles and spermatid basal bodies are short in length. bld10 mutant flies are viable but male sterile, producing immotile sperm whose axonemes are deficient in the central pair of microtubules. These results show that Drosophila Bld10 is required for centriole and axoneme assembly to confer cilium motility.

scholarly journals Cyclase-associated Protein (CAP) Acts Directly on F-actin to Accelerate Cofilin-mediated Actin Severing across the Range of Physiological pH

2012 ◽  
Vol 287 (42) ◽  
pp. 35722-35732 ◽  
Author(s):  
Kieran P. M. Normoyle ◽  
William M. Brieher
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Mammalian Cells ◽  
Actin Dynamics ◽  
Turnover Rates ◽  
Interacting Protein ◽  
Actin Depolymerization ◽  
Neutral Ph ◽  
Filament Networks ◽  
Actin Comet Tails

Fast actin depolymerization is necessary for cells to rapidly reorganize actin filament networks. Utilizing a Listeria fluorescent actin comet tail assay to monitor actin disassembly rates, we observed that although a mixture of actin disassembly factors (cofilin, coronin, and actin-interacting protein 1 is sufficient to disassemble actin comet tails in the presence of physiological G-actin concentrations this mixture was insufficient to disassemble actin comet tails in the presence of physiological F-actin concentrations. Using biochemical complementation, we purified cyclase-associated protein (CAP) from thymus extracts as a factor that protects against the inhibition of excess F-actin. CAP has been shown to participate in actin dynamics but has been thought to act by liberating cofilin from ADP·G-actin monomers to restore cofilin activity. However, we found that CAP augments cofilin-mediated disassembly by accelerating the rate of cofilin-mediated severing. We also demonstrated that CAP acts directly on F-actin and severs actin filaments at acidic, but not neutral, pH. At the neutral pH characteristic of cytosol in most mammalian cells, we demonstrated that neither CAP nor cofilin are capable of severing actin filaments. However, the combination of CAP and cofilin rapidly severed actin at all pH values across the physiological range. Therefore, our results reveal a new function for CAP in accelerating cofilin-mediated actin filament severing and provide a mechanism through which cells can maintain high actin turnover rates without having to alkalinize cytosol, which would affect many biochemical reactions beyond actin depolymerization.

scholarly journals Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone

2020 ◽  
Author(s):  
Antonia Wiegering ◽  
Renate Dildrop ◽  
Christine Vesque ◽  
Sylvie Schneider-Maunoury ◽  
Christoph Gerhardt
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Primary Cilia ◽  
Human Diseases ◽  
Entry And Exit ◽  
Ciliary Protein ◽  
Genes Encoding ◽  
Mother Centriole ◽  
Protein Entry

AbstractA range of severe human diseases called ciliopathies are caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localise to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.

scholarly journals NEK9 regulates primary cilia formation by acting as a selective autophagy adaptor for MYH9/myosin IIA

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yasuhiro Yamamoto ◽  
Haruka Chino ◽  
Satoshi Tsukamoto ◽  
Koji L. Ode ◽  
Hiroki R. Ueda ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Underlying Mechanism ◽  
Actin Network ◽  
Interacting Protein ◽  
Cilia Formation ◽  
Terrestrial Life ◽  
Myosin Iia ◽  
Mutant Cells ◽  
Land Vertebrates

AbstractAutophagy regulates primary cilia formation, but the underlying mechanism is not fully understood. In this study, we identify NIMA-related kinase 9 (NEK9) as a GABARAPs-interacting protein and find that NEK9 and its LC3-interacting region (LIR) are required for primary cilia formation. Mutation in the LIR of NEK9 in mice also impairs in vivo cilia formation in the kidneys. Mechanistically, NEK9 interacts with MYH9 (also known as myosin IIA), which has been implicated in inhibiting ciliogenesis through stabilization of the actin network. MYH9 accumulates in NEK9 LIR mutant cells and mice, and depletion of MYH9 restores ciliogenesis in NEK9 LIR mutant cells. These results suggest that NEK9 regulates ciliogenesis by acting as an autophagy adaptor for MYH9. Given that the LIR in NEK9 is conserved only in land vertebrates, the acquisition of the autophagic regulation of the NEK9–MYH9 axis in ciliogenesis may have possible adaptive implications for terrestrial life.

scholarly journals The novel centriolar satellite protein SSX2IP targets Cep290 to the ciliary transition zone

2014 ◽  
Vol 25 (4) ◽  
pp. 495-507 ◽  
Author(s):  
Maren Klinger ◽  
Wenbo Wang ◽  
Stefanie Kuhns ◽  
Felix Bärenz ◽  
Stefanie Dräger-Meurer ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Basal Body ◽  
Primary Cilia ◽  
Protein Targeting ◽  
Somatostatin Receptor ◽  
Human Cells ◽  
Interacting Protein ◽  
Ciliary Membrane ◽  
Intracellular Signals

In differentiated human cells, primary cilia fulfill essential functions in converting mechanical or chemical stimuli into intracellular signals. Formation and maintenance of cilia require multiple functions associated with the centriole-derived basal body, from which axonemal microtubules grow and which assembles a gate to maintain the specific ciliary proteome. Here we characterize the function of a novel centriolar satellite protein, synovial sarcoma X breakpoint–interacting protein 2 (SSX2IP), in the assembly of primary cilia. We show that SSX2IP localizes to the basal body of primary cilia in human and murine ciliated cells. Using small interfering RNA knockdown in human cells, we demonstrate the importance of SSX2IP for efficient recruitment of the ciliopathy-associated satellite protein Cep290 to both satellites and the basal body. Cep290 takes a central role in gating proteins to the ciliary compartment. Consistent with that, loss of SSX2IP drastically reduces entry of the BBSome, which functions to target membrane proteins to primary cilia, and interferes with efficient accumulation of the key regulator of ciliary membrane protein targeting, Rab8. Finally, we show that SSX2IP knockdown limits targeting of the ciliary membrane protein and BBSome cargo, somatostatin receptor 3, and significantly reduces axoneme length. Our data establish SSX2IP as a novel targeting factor for ciliary membrane proteins cooperating with Cep290, the BBSome, and Rab8.

scholarly journals Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone

2021 ◽  
pp. mbc.E20-03-0190
Author(s):  
Antonia Wiegering ◽  
Renate Dildrop ◽  
Christine Vesque ◽  
Hemant Khanna ◽  
Sylvie Schneider-Maunoury ◽  
...  
Keyword(s):  
Transition Zone ◽  
Basal Body ◽  
Primary Cilia ◽  
Human Diseases ◽  
Entry And Exit ◽  
Ciliary Protein ◽  
Genes Encoding ◽  
Mother Centriole ◽  
Protein Entry

A range of severe human diseases called ciliopathies are caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localise to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.

scholarly journals The E3 ubiquitin ligase UBR5 regulates centriolar satellite stability and primary cilia formation via ubiquitylation of CSPP-L

2016 ◽  
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

AbstractPrimary 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 modulator of ciliogenesis in a functional genomics screen. UBR5 is an E3 Ubiquitin ligase that is frequently deregulated in tumours, but its biological role in cancer is largely uncharacterised, 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. Hence, we have established a key role for UBR5 in ciliogenesis that may have important implications in understanding cancer pathophysiology.

scholarly journals Protein Kinase A-Mediated Septin7 Phosphorylation Disrupts Septin Filaments and Ciliogenesis

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 361
Author(s):  
Han-Yu Wang ◽  
Chun-Hsiang Lin ◽  
Yi-Ru Shen ◽  
Ting-Yu Chen ◽  
Chia-Yih Wang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Primary Cilia ◽  
Cell Growth And Migration ◽  
Filament Dynamics ◽  
Gtp Binding ◽  
Cilia Formation ◽  
And Migration ◽  
Septin Filament ◽  
Kinase A

Septins are GTP-binding proteins that form heteromeric filaments for proper cell growth and migration. Among the septins, septin7 (SEPT7) is an important component of all septin filaments. Here we show that protein kinase A (PKA) phosphorylates SEPT7 at Thr197, thus disrupting septin filament dynamics and ciliogenesis. The Thr197 residue of SEPT7, a PKA phosphorylating site, was conserved among different species. Treatment with cAMP or overexpression of PKA catalytic subunit (PKACA2) induced SEPT7 phosphorylation, followed by disruption of septin filament formation. Constitutive phosphorylation of SEPT7 at Thr197 reduced SEPT7‒SEPT7 interaction, but did not affect SEPT7‒SEPT6‒SEPT2 or SEPT4 interaction. Moreover, we noted that SEPT7 interacted with PKACA2 via its GTP-binding domain. Furthermore, PKA-mediated SEPT7 phosphorylation disrupted primary cilia formation. Thus, our data uncover the novel biological function of SEPT7 phosphorylation in septin filament polymerization and primary cilia formation.

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