scholarly journals Ciliopathy protein HYLS1 coordinates the biogenesis and signaling of primary cilia by activating the ciliary lipid kinase PIPKIγ

2021 ◽  
Vol 7 (26) ◽  
pp. eabe3401
Author(s):  
Chuan Chen ◽  
Qingwen Xu ◽  
Yuxia Zhang ◽  
Brian A. Davies ◽  
Yan Huang ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Direct Interaction ◽  
Lipid Kinase ◽  
Molecular Etiology ◽  
Hh Signaling ◽  
Phosphatidylinositol 4 ◽  
Ciliary Signaling

Mutation of ciliopathy protein HYLS1 causes the perinatal lethal hydrolethalus syndrome (HLS), yet the underlying molecular etiology and pathogenesis remain elusive. Here, we reveal unexpected mechanistic insights into the role of mammalian HYLS1 in regulating primary cilia. HYLS1 is recruited to the ciliary base via a direct interaction with the type Iγ phosphatidylinositol 4-phosphate [PI(4)P] 5-kinase (PIPKIγ). HYLS1 activates PIPKIγ by interrupting the autoinhibitory dimerization of PIPKIγ, which thereby expedites depletion of centrosomal PI(4)P to allow axoneme nucleation. HYLS1 deficiency interrupts the assembly of ciliary NPHP module and agonist-induced ciliary exit of β-arrestin, which, in turn, disturbs the removal of ciliary Gpr161 and activation of hedgehog (Hh) signaling. Consistent with this model of pathogenesis, the HLS mutant HYLS1D211G supports ciliogenesis but not activation of Hh signaling. These results implicate mammalian HYLS1 as a multitasking protein that facilitates ciliogenesis and ciliary signaling by coordinating with the ciliary lipid kinase PIPKIγ.

Physiological role of primary cilia in glial cells as a biosensor for the Hh signaling pathway

2009 ◽  
Vol 65 ◽  
pp. S88
Author(s):  
Kentaro Yoshimura ◽  
Toyoko Kawate ◽  
Sen Takeda
Keyword(s):  
Signaling Pathway ◽  
Glial Cells ◽  
Primary Cilia ◽  
Physiological Role ◽  
Hh Signaling

scholarly journals Nucleocytoplasmic Shuttling of the Golgi Phosphatidylinositol 4-Kinase Pik1 Is Regulated by 14-3-3 Proteins and Coordinates Golgi Function with Cell Growth

2008 ◽  
Vol 19 (3) ◽  
pp. 1046-1061 ◽  
Author(s):  
Lars Demmel ◽  
Mike Beck ◽  
Christian Klose ◽  
Anne-Lore Schlaitz ◽  
Yvonne Gloor ◽  
...  
Keyword(s):  
Nutrient Supply ◽  
Nucleocytoplasmic Shuttling ◽  
Lipid Kinase ◽  
Golgi Transport ◽  
Dual Localization ◽  
Transport Vesicles ◽  
Catalytically Active ◽  
Nutrient Signaling ◽  
Phosphatidylinositol 4

The yeast phosphatidylinositol 4-kinase Pik1p is essential for proliferation, and it controls Golgi homeostasis and transport of newly synthesized proteins from this compartment. At the Golgi, phosphatidylinositol 4-phosphate recruits multiple cytosolic effectors involved in formation of post-Golgi transport vesicles. A second pool of catalytically active Pik1p localizes to the nucleus. The physiological significance and regulation of this dual localization of the lipid kinase remains unknown. Here, we show that Pik1p binds to the redundant 14-3-3 proteins Bmh1p and Bmh2p. We provide evidence that nucleocytoplasmic shuttling of Pik1p involves phosphorylation and that 14-3-3 proteins bind Pik1p in the cytoplasm. Nutrient deprivation results in relocation of Pik1p from the Golgi to the nucleus and increases the amount of Pik1p–14-3-3 complex, a process reversed upon restored nutrient supply. These data suggest a role of Pik1p nucleocytoplasmic shuttling in coordination of biosynthetic transport from the Golgi with nutrient signaling.

scholarly journals Primary Cilia Mediate TSH-Regulated Thyroglobulin Endocytic Pathways

2021 ◽  
Vol 12 ◽  
Author(s):  
Junguee Lee ◽  
Hae Joung Sul ◽  
Kun-Ho Kim ◽  
Joon Young Chang ◽  
Minho Shong
Keyword(s):  
Thyroid Gland ◽  
Primary Cilium ◽  
Untreated Control ◽  
Primary Cilia ◽  
Apical Surface ◽  
Follicular Cells ◽  
Thyroid Follicular Cells ◽  
Ciliary Signaling ◽  
Endocytic Pathways

Primary cilia are sensory organelles with a variety of receptors and channels on their membranes. Recently, primary cilia were proposed to be crucial sites for exocytosis and endocytosis of vesicles associated with endocytic control of various ciliary signaling pathways. Thyroglobulin (Tg) synthesis and Tg exocytosis/endocytosis are critical for the functions of thyroid follicular cells, where primary cilia are relatively well preserved. LRP2/megalin has been detected on the apical surface of absorptive epithelial cells, including thyrocytes. LRP2/megalin on thyrocytes serves as a Tg receptor and can mediate Tg endocytosis. In this study, we investigated the role of primary cilia in LRP2/megalin expression in thyroid gland stimulated with endogenous TSH using MMI-treated and Tg-Cre;Ift88flox/flox mice. LRP2/megalin expression in thyroid follicles was higher in MMI-treated mice than in untreated control mice. MMI-treated mice exhibited a significant increase in ciliogenesis in thyroid follicular cells relative to untreated controls. Furthermore, MMI-induced ciliogenesis accompanied increases in LRP2/megalin expression in thyroid follicular cells, in which LRP2/megalin was localized to the primary cilium. By contrast, in Tg-Cre;Ift88flox/flox mice, thyroid with defective primary cilia expressed markedly lower levels of LRP2/megalin. Serum Tg levels were elevated in MMI-treated mice and reduced in Tg-Cre;Ift88flox/flox mice. Taken together, these results indicate that defective ciliogenesis in murine thyroid follicular cells is associated with impaired LRP2/megalin expression and reduced serum Tg levels. Our results strongly suggest that primary cilia harbors LRP2/megalin, and are involved in TSH-mediated endocytosis of Tg in murine thyroid follicles.

scholarly journals Ciliary signaling-patterned smooth muscle drives tubular elongation

2020 ◽  
Author(s):  
Ying Yang ◽  
Pekka Paivinen ◽  
Chang Xie ◽  
Alexis Leigh Krup ◽  
Tomi P. Makela ◽  
...  
Keyword(s):  
Residual Stress ◽  
Smooth Muscle ◽  
Small Intestine ◽  
Embryonic Development ◽  
Primary Cilia ◽  
Tissue Mechanics ◽  
Longitudinal Growth ◽  
List Type ◽  
Hh Signaling ◽  
Ciliary Signaling

SummaryDuring development, many tubular organs undergo extensive longitudinal growth to reach their defined length, essential for their function, but how they lengthen is poorly understood. Here, we found that primary cilia are critical for the elongation of the small intestine and esophagus during murine embryonic development. More specifically, HH ligands produced by the epithelium signaled via cilia in the surrounding mesenchyme to pattern the smooth muscle. Like attenuated ciliary HH signaling, partial ablation of the smooth muscle reduced elongation, revealing an essential role for smooth muscle in longitudinal growth. Disruption of cilia, HH signaling or the smooth muscle reduced residual stress within the gut wall, indicating that smooth muscle contributes to the mechanical properties of the developing gut. Reducing residual stress decreased nuclear YAP, an effector of the mechanotransductive Hippo pathway. Removing YAP in the mesenchyme did not affect smooth muscle formation, but attenuated proliferation and elongation, demonstrating that YAP interprets smooth muscle-generated force to promote proliferation. Together, our results reveal that ciliary signaling directs the formation of the smooth muscle layer which, in turn, generates mechanical forces that activate YAP-mediated proliferation. As this interplay of biochemical and mechanical signals drives elongation of both the esophagus and small intestine, we propose that this mechanism may underlie tubular organ elongation generally.HighlightsPrimary cilia are essential for the elongation of the small intestine and esophagus during embryonic developmentCiliary signaling patterns the smooth muscle in the developing intestine and esophagusThe smooth muscle contributes to tissue mechanicsSmooth muscle-generated strain activates YAP to drive longitudinal growth of the tubular organs

scholarly journals Centrin2 regulates CP110 removal in primary cilium formation

2015 ◽  
Vol 208 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Ciaran G. Morrison
Keyword(s):  
Calcium Binding ◽  
Primary Cilia ◽  
Reverse Genetics ◽  
Cell Types ◽  
Serum Starvation ◽  
Basal Bodies ◽  
Cilium Formation ◽  
Cellular Quiescence ◽  
Retinal Pigmented Epithelial Cells

Primary cilia are antenna-like sensory microtubule structures that extend from basal bodies, plasma membrane–docked mother centrioles. Cellular quiescence potentiates ciliogenesis, but the regulation of basal body formation is not fully understood. We used reverse genetics to test the role of the small calcium-binding protein, centrin2, in ciliogenesis. Primary cilia arise in most cell types but have not been described in lymphocytes. We show here that serum starvation of transformed, cultured B and T cells caused primary ciliogenesis. Efficient ciliogenesis in chicken DT40 B lymphocytes required centrin2. We disrupted CETN2 in human retinal pigmented epithelial cells, and despite having intact centrioles, they were unable to make cilia upon serum starvation, showing abnormal localization of distal appendage proteins and failing to remove the ciliation inhibitor CP110. Knockdown of CP110 rescued ciliation in CETN2-deficient cells. Thus, centrin2 regulates primary ciliogenesis through controlling CP110 levels.

scholarly journals The Lipid Kinase Phosphatidylinositol-4 Kinase III Alpha Regulates the Phosphorylation Status of Hepatitis C Virus NS5A

2013 ◽  
Vol 9 (5) ◽  
pp. e1003359 ◽  
Author(s):  
Simon Reiss ◽  
Christian Harak ◽  
Inés Romero-Brey ◽  
Danijela Radujkovic ◽  
Rahel Klein ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Lipid Kinase ◽  
Phosphatidylinositol 4

scholarly journals Osteoarthritis-Like Changes in Bardet–Biedl Syndrome Mutant Ciliopathy Mice (Bbs1M390R/M390R): Evidence for a Role of Primary Cilia in Cartilage Homeostasis and Regulation of Inflammation

2018 ◽  
Vol 9 ◽  
Author(s):  
Isaac D. Sheffield ◽  
Mercedes A. McGee ◽  
Steven J. Glenn ◽  
Da Young Baek ◽  
Joshua M. Coleman ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Bardet Biedl Syndrome ◽  
Cartilage Homeostasis

scholarly journals Positive Regulation of fur Gene Expression via Direct Interaction of Fur in a Pathogenic Bacterium, Vibrio vulnificus

2007 ◽  
Vol 189 (7) ◽  
pp. 2629-2636 ◽  
Author(s):  
Hyun-Jung Lee ◽  
So Hyun Bang ◽  
Kyu-Ho Lee ◽  
Soon-Jung Park
Keyword(s):  
Gene Expression ◽  
Pathogenic Bacteria ◽  
Vibrio Vulnificus ◽  
Iron Concentration ◽  
Direct Interaction ◽  
Repeated Sequence ◽  
Upstream Region ◽  
Fur Protein

ABSTRACT In pathogenic bacteria, the ability to acquire iron, which is mainly regulated by the ferric uptake regulator (Fur), is essential to maintain growth as well as its virulence. In Vibrio vulnificus, a human pathogen causing gastroenteritis and septicemia, fur gene expression is positively regulated by Fur when the iron concentration is limited (H.-J. Lee et al., J. Bacteriol. 185:5891-5896, 2003). Footprinting analysis revealed that an upstream region of the fur gene was protected by the Fur protein from DNase I under iron-depleted conditions. The protected region, from −142 to −106 relative to the transcription start site of the fur gene, contains distinct AT-rich repeats. Mutagenesis of this repeated sequence resulted in abolishment of binding by Fur. To confirm the role of this cis-acting element in Fur-mediated control of its own gene in vivo, fur expression was monitored in V. vulnificus strains using a transcriptional fusion containing the mutagenized Fur-binding site (fur mt::luxAB). Expression of fur mt::luxAB showed that it was not regulated by Fur and was not influenced by iron concentration. Therefore, this study demonstrates that V. vulnificus Fur acts as a positive regulator under iron-limited conditions by direct interaction with the fur upstream region.

Polaris, a protein disrupted inorpkmutant mice, is required for assembly of renal cilium

2002 ◽  
Vol 282 (3) ◽  
pp. F541-F552 ◽  
Author(s):  
Bradley K. Yoder ◽  
Albert Tousson ◽  
Leigh Millican ◽  
John H. Wu ◽  
Charles E. Bugg ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Collecting Duct ◽  
Physiological Role ◽  
Duct Cell ◽  
Cystic Kidney Disease ◽  
Cystic Kidney ◽  
Apical Surface ◽  
Cystic Disease ◽  
Cortical Collecting Duct

Cilia are organelles that play diverse roles, from fluid movement to sensory reception. Polaris, a protein associated with cystic kidney disease in Tg737°rpkmice, functions in a ciliogenic pathway. Here, we explore the role of polaris in primary cilia on Madin-Darby canine kidney cells. The results indicate that polaris localization and solubility change dramatically during cilia formation. These changes correlate with the formation of basal bodies and large protein rafts at the apical surface of the epithelia. A cortical collecting duct cell line has been derived from mice with a mutation in the Tg737 gene. These cells do not develop normal cilia, which can be corrected by reexpression of the wild-type Tg737 gene. These data suggest that the primary cilia are important for normal renal function and/or development and that the ciliary defect may be a contributing factor to the cystic disease in Tg737°rpkmice. Further characterization of these cells will be important in elucidating the physiological role of renal cilia and in determining their relationship to cystic disease.

scholarly journals Hepatitis C Virus Subverts Human Choline Kinase-α To Bridge Phosphatidylinositol-4-Kinase IIIα (PI4KIIIα) and NS5A and Upregulates PI4KIIIα Activation, Thereby Promoting the Translocation of the Ternary Complex to the Endoplasmic Reticulum for Viral Replication

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Mun-Teng Wong ◽  
Steve S. Chen
Keyword(s):  
Endoplasmic Reticulum ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Viral Replication ◽  
Ternary Complex ◽  
Choline Kinase ◽  
Replication Complex ◽  
Viral Replication Complex ◽  
Phosphatidylinositol 4

ABSTRACT In this study, we elucidated the mechanism by which human choline kinase-α (hCKα) interacts with nonstructural protein 5A (NS5A) and phosphatidylinositol-4-kinase IIIα (PI4KIIIα), the lipid kinase crucial for maintaining the integrity of virus-induced membranous webs, and modulates hepatitis C virus (HCV) replication. hCKα activity positively modulated phosphatidylinositol-4-phosphate (PI4P) levels in HCV-expressing cells, and hCKα-mediated PI4P accumulation was abolished by AL-9, a PI4KIIIα-specific inhibitor. hCKα colocalized with NS5A and PI4KIIIα or PI4P; NS5A expression increased hCKα and PI4KIIIα colocalization; and hCKα formed a ternary complex with PI4KIIIα and NS5A, supporting the functional interplay of hCKα with PI4KIIIα and NS5A. PI4KIIIα inactivation by AL-9 or hCKα inactivation by CK37, a specific hCKα inhibitor, impaired the endoplasmic reticulum (ER) localization and colocalization of these three molecules. Interestingly, hCKα knockdown or inactivation inhibited PI4KIIIα-NS5A binding. In an in vitro PI4KIIIα activity assay, hCKα activity slightly increased PI4KIIIα basal activity but greatly augmented NS5A-induced PI4KIIIα activity, supporting the essential role of ternary complex formation in robust PI4KIIIα activation. Concurring with the upregulation of PI4P production and viral replication, overexpression of active hCKα-R (but not the D288A mutant) restored PI4KIIIα and NS5A translocation to the ER in hCKα stable knockdown cells. Furthermore, active PI4KIIIα overexpression restored PI4P production, PI4KIIIα and NS5A translocation to the ER, and viral replication in CK37-treated cells. Based on our results, hCKα functions as an indispensable regulator that bridges PI4KIIIα and NS5A and potentiates NS5A-stimulated PI4KIIIα activity, which then facilitates the targeting of the ternary complex to the ER for viral replication. IMPORTANCE The mechanisms by which hCKα activity modulates the transport of the hCKα-NS5A complex to the ER are not understood. In the present study, we investigated how hCKα interacts with PI4KIIIα (a key element that maintains the integrity of the “membranous web” structure) and NS5A to regulate viral replication. We demonstrated that HCV hijacks hCKα to bridge PI4KIIIα and NS5A, forming a ternary complex, which then stimulates PI4KIIIα activity to produce PI4P. Pronounced PI4P synthesis then redirects the translocation of the ternary complex to the ER-derived, PI4P-enriched membrane for assembly of the viral replication complex and viral replication. Our study provides novel insights into the indispensable modulatory role of hCKα in the recruitment of PI4KIIIα to NS5A and in NS5A-stimulated PI4P production and reveals a new perspective for understanding the impact of profound PI4KIIIα activation on the targeting of PI4KIIIα and NS5A to the PI4P-enriched membrane for viral replication complex formation.

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