• Title, Summary, Keyword: Ciliopathies

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Ciliary subcompartments: how are they established and what are their functions?

  • Lee, Jeongmi;Chung, Yun Doo
    • BMB Reports
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    • v.48 no.7
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    • pp.380-387
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    • 2015
  • Cilia are conserved subcellular organelles with diverse sensory and developmental roles. Recently, they have emerged as crucial organelles whose dysfunction causes a wide spectrum of disorders called ciliopathies. Recent studies on the pathological mechanisms underlying ciliopathies showed that the ciliary compartment is further divided into subdomains with specific roles in the biogenesis, maintenance and function of cilia. Several conserved sets of molecules that play specific roles in each subcompartment have been discovered. Here we review recent progress on our understanding of ciliary subcompartments, especially focusing on the molecules required for their structure and/or function. [BMB Reports 2015; 48(7): 380-387]

Interplay Between Primary Cilia and Autophagy and Its Controversial Roles in Cancer

  • Ko, Je Yeong;Lee, Eun Ji;Park, Jong Hoon
    • Biomolecules & Therapeutics
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    • v.27 no.4
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    • pp.337-341
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    • 2019
  • Primary cilia and autophagy are two distinct nutrient-sensing machineries required for maintaining intracellular energy homeostasis, either via signal transduction or recycling of macromolecules from cargo breakdown, respectively. Potential correlations between primary cilia and autophagy have been recently suggested and their relationship may increase our understanding of the pathogenesis of human diseases, including ciliopathies and cancer. In this review, we cover the current issues concerning the bidirectional interaction between primary cilia and autophagy and discuss its role in cancer with cilia defect.

Deficiency of calpain-6 inhibits primary ciliogenesis

  • Kim, Bo Hye;Kim, Do Yeon;Oh, Sumin;Ko, Je Yeong;Rah, Gyuyeong;Yoo, Kyung Hyun;Park, Jong Hoon
    • BMB Reports
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    • v.52 no.10
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    • pp.619-624
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    • 2019
  • The primary cilium is a microtubule-based structure projecting from a cell. Although the primary cilium shows no motility, it can recognize environmental stimuli. Thus, ciliary defects cause severe abnormalities called ciliopathies. Ciliogenesis is a very complex process and involves a myriad of components and regulators. In order to excavate the novel positive regulators of ciliogenesis, we performed mRNA microarray using starved NIH/3T3 cells. We selected 62 murine genes with corresponding human orthologs, with significantly upregulated expression at 24 h after serum withdrawal. Finally, calpain-6 was selected as a positive regulator of ciliogenesis. We found that calpain-6 deficiency reduced the percentage of ciliated cells and impaired sonic hedgehog signaling. It has been speculated that this defect might be associated with decreased levels of ${\alpha}-tubulin$ acetylation at lysine 40. This is the first study to report a novel role of calpain-6 in the formation of primary cilia.

Two siblings with Bardet-Biedl syndrome caused by mutations in BBS10 : the first case identified in Korea

  • Yoon, Sung Chul;Lee, Hye Jin;Ko, Jung Min;Kang, Hee Gyung;Cheong, Hae Il;Yu, Hyeong Gon;Kim, Jae Hyung
    • Journal of Genetic Medicine
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    • v.11 no.1
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    • pp.31-35
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    • 2014
  • Bardet-Biedl syndrome (BBS) is a rare ciliopathy generally inherited with an autosomal recessive pattern. BBS is characterized by 6 primary features namely retinal dystrophy, obesity, postaxial polydactyly, renal dysfunction, learning difficulties, and hypogonadism and a wide range of secondary features. To date, mutations in 16 genes have been identified as causative factors for BBS. Among them, the BBS1 and BBS10 genes are major disease-causing genes, and each of these gene mutations presents in more than 20% of all BBS patients. Genotype-phenotype correlations have not been observed in BBS, and there can be phenotypic overlap between BBS and other ciliopathies. In Korea, no molecular, genetically confirmed case of BBS has been reported to date. Herein, we describe the case of the first Korean siblings with BBS resulting from 2 BBS10 gene mutations who showed typical clinical phenotypes, including retinal dystrophy, obesity, intellectual disability, cystic tubular disease, and postaxial polydactyly.

Autophagy Regulates Formation of Primary Cilia in Mefloquine-Treated Cells

  • Shin, Ji Hyun;Bae, Dong-Jun;Kim, Eun Sung;Kim, Han Byeol;Park, So Jung;Jo, Yoon Kyung;Jo, Doo Sin;Jo, Dong-Gyu;Kim, Sang-Yeob;Cho, Dong-Hyung
    • Biomolecules & Therapeutics
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    • v.23 no.4
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    • pp.327-332
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    • 2015
  • Primary cilia have critical roles in coordinating multiple cellular signaling pathways. Dysregulation of primary cilia is implicated in various ciliopathies. To identify specific regulators of autophagy, we screened chemical libraries and identified mefloquine, an anti-malaria medicine, as a potent regulator of primary cilia in human retinal pigmented epithelial (RPE) cells. Not only ciliated cells but also primary cilium length was increased in mefloquine-treated RPE cells. Treatment with mefloquine strongly induced the elongation of primary cilia by blocking disassembly of primary cilium. In addition, we found that autophagy was increased in mefloquine-treated cells by enhancing autophagic flux. Both chemical and genetic inhibition of autophagy suppressed ciliogenesis in mefloquine-treated RPE cells. Taken together, these results suggest that autophagy induced by mefloquine positively regulates the elongation of primary cilia in RPE cells.

Primary cilia in energy balance signaling and metabolic disorder

  • Lee, Hankyu;Song, Jieun;Jung, Joo Hyun;Ko, Hyuk Wan
    • BMB Reports
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    • v.48 no.12
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    • pp.647-654
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    • 2015
  • Energy homeostasis in our body system is maintained by balancing the intake and expenditure of energy. Excessive accumulation of fat by disrupting the balance system causes overweight and obesity, which are increasingly becoming global health concerns. Understanding the pathogenesis of obesity focused on studying the genes related to familial types of obesity. Recently, a rare human genetic disorder, ciliopathy, links the role for genes regulating structure and function of a cellular organelle, the primary cilium, to metabolic disorder, obesity and type II diabetes. Primary cilia are microtubule based hair-like membranous structures, lacking motility and functions such as sensing the environmental cues, and transducing extracellular signals within the cells. Interestingly, the subclass of ciliopathies, such as Bardet-Biedle and Alström syndrome, manifest obesity and type II diabetes in human and mouse model systems. Moreover, studies on genetic mouse model system indicate that more ciliary genes affect energy homeostasis through multiple regulatory steps such as central and peripheral actions of leptin and insulin. In this review, we discuss the latest findings in primary cilia and metabolic disorders, and propose the possible interaction between primary cilia and the leptin and insulin signal pathways which might enhance our understanding of the unambiguous link of a cell's antenna to obesity and type II diabetes.

The primary cilium as a multiple cellular signaling scaffold in development and disease

  • Ko, Hyuk-Wan
    • BMB Reports
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    • v.45 no.8
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    • pp.427-432
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    • 2012
  • Primary cilia, single hair-like appendage on the surface of the most mammalian cells, were once considered to be vestigial cellular organelles for a past century because of their tiny structure and unknown function. Although they lack ancestral motility function of cilia or flagella, they share common ground with multiciliated motile cilia and flagella on internal structure such as microtubule based nine outer doublets nucleated from the base of mother centrioles called basal body. Making cilia, ciliogenesis, in cells depends on the cell cycle stage due to reuse of centrioles for cell division forming mitotic spindle pole (M phase) and assembling cilia from basal body (starting G1 phase and maintaining most of interphase). Ciliary assembly required two conflicting processes such as assembly and disassembly and balance between these two processes determines the length of cilia. Both process required highly conserved transport system to supply needed substance to grow tip of cilia and bring ciliary turnover product back to the base of cilia using motor protein, kinesin and dynein, and transport protein complex, IFT particles. Disruption of ciliary structure or function causes multiple human disorder called ciliopathies affecting disease of diverse ciliated tissues ranging from eye, kidney, respiratory tract and brain. Recent explosion of research on the primary cilia and their involvement on animal development and disease attracts scientific interest on how extensively the function of cilia related to specific cell physiology and signaling pathway. In this review, I introduce general features of primary cilia and recent progress in understanding of the ciliary length control and signaling pathways transduced through primary cilia in vertebrates.

Clinical features of Senior-Loken syndrome with IQCB1/NPHP5 mutation in a Filipino man

  • Chiu, Harold Henrison C.;Sucaldito, Ma. Sergia Fatima P.;Maceda, Ebner Bon G.;Montemayor, Jan Andre S.;Tamondong-Lachica, Diana R.
    • Journal of Genetic Medicine
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    • v.17 no.1
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    • pp.39-42
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    • 2020
  • The Senior-Loken syndrome was first described in 1961 as an oculo-renal disease consisting of familial juvenile nephronophthisis and Leber congenital amaurosis. It is a rare autosomal recessive disorder with a prevalence of 1:1,000,000 caused by mutations in nine genes (NPHP 1-8 and NPHP 10). Ocular manifestations (e.g., photophobia, nystagmus, and extreme hyperopia) occur within the first few years of life while renal manifestations (e.g., formation of multiple cysts impairing kidney function and end-stage renal disease) appear in late childhood to adolescence. Here, we report a case of a Filipino male presenting with rotatory nystagmus and progressive deterioration of vision since childhood. He had congenital amaurosis and juvenile nephronophthisis that progressed to end stage renal disease by age 19. All laboratory and imaging findings were consistent with chronic kidney disease. Molecular genetic testing of ciliopathy-related genes was performed revealing a homozygous mutation in exon 11 of the IQCB1/NPHP5 gene, c.1090C>T (p.Arg364⁎). This sequence change created a premature translational stop signal resulting in a truncated protein product, nephrocystin-5 and its consequent loss of function. His symptoms eventually improved with initiation dialysis. The prognosis of Senior-Loken syndrome remains dismal and a high index of suspicion, early diagnosis and timely intervention of renal complications are warranted.