scholarly journals The microtubule affinity regulating kinase MARK4 promotes axoneme extension during early ciliogenesis

2013 ◽  
Vol 200 (4) ◽  
pp. 505-522 ◽  
Author(s):  
Stefanie Kuhns ◽  
Kerstin N. Schmidt ◽  
Jürgen Reymann ◽  
Daniel F. Gilbert ◽  
Annett Neuner ◽  
...  
Keyword(s):  
Rna Interference ◽  
Protein Kinases ◽  
Basal Body ◽  
Kinase Activity ◽  
Complete Removal ◽  
Cilia Formation ◽  
Mother Centriole ◽  
Functional Analyses ◽  
Novel Protein

Despite the critical contributions of cilia to embryonic development and human health, key regulators of cilia formation await identification. In this paper, a functional RNA interference–based screen linked 30 novel protein kinases with ciliogenesis. Of them, we have studied the role of the microtubule (MT)-associated protein/MT affinity regulating kinase 4 (MARK4) in depth. MARK4 associated with the basal body and ciliary axoneme in human and murine cell lines. Ultrastructural and functional analyses established that MARK4 kinase activity was required for initiation of axoneme extension. We identified the mother centriolar protein ODF2 as an interaction partner of MARK4 and showed that ODF2 localization to the centriole partially depended on MARK4. Our data indicated that, upon MARK4 or ODF2 knockdown, the ciliary program arrested before the complete removal of the CP110–Cep97 inhibitory complex from the mother centriole, suggesting that these proteins act at this level of axonemal extension. We propose that MARK4 is a critical positive regulator of early steps in ciliogenesis.

scholarly journals The kinase activity of human Rio1 is required for final steps of cytoplasmic maturation of 40S subunits

2012 ◽  
Vol 23 (1) ◽  
pp. 22-35 ◽  
Author(s):  
Barbara Widmann ◽  
Franziska Wandrey ◽  
Lukas Badertscher ◽  
Emanuel Wyler ◽  
Jens Pfannstiel ◽  
...  
Keyword(s):  
Rna Interference ◽  
Protein Kinases ◽  
18S Rrna ◽  
Kinase Activity ◽  
Ribosomal Biogenesis ◽  
Ribosomal Subunits ◽  
Binding Partner ◽  
Rrna Maturation ◽  
Cytoplasmic Maturation

RIO proteins form a conserved family of atypical protein kinases. Humans possess three distinct RIO kinases—hRio1, hRio2, and hRio3, of which only hRio2 has been characterized with respect to its role in ribosomal biogenesis. Here we show that both hRio1 and hRio3, like hRio2, are associated with precursors of 40S ribosomal subunits in human cells. Furthermore, we demonstrate that depletion of hRio1 by RNA interference affects the last step of 18S rRNA maturation and causes defects in the recycling of several trans-acting factors (hEnp1, hRio2, hLtv1, hDim2/PNO1, and hNob1) from pre-40S subunits in the cytoplasm. Although the effects of hRio1 and hRio2 depletion are similar, we show that the two kinases are not fully interchangeable. Moreover, rescue experiments with a kinase-dead mutant of hRio1 revealed that the kinase activity of hRio1 is essential for the recycling of the endonuclease hNob1 and its binding partner hDim2 from cytoplasmic pre-40S. Kinase-dead hRio1 is trapped on pre-40S particles containing hDim2 and hNob1 but devoid of hEnp1, hLtv1, and hRio2. These data reveal a role of hRio1 in the final stages of cytoplasmic pre-40S maturation.

scholarly journals Cep164 mediates vesicular docking to the mother centriole during early steps of ciliogenesis

2012 ◽  
Vol 199 (7) ◽  
pp. 1083-1101 ◽  
Author(s):  
Kerstin N. Schmidt ◽  
Stefanie Kuhns ◽  
Annett Neuner ◽  
Birgit Hub ◽  
Hanswalter Zentgraf ◽  
...  
Keyword(s):  
Basal Body ◽  
Distal Part ◽  
Membrane Biogenesis ◽  
Step Process ◽  
Ciliary Membrane ◽  
Functional Assays ◽  
Apical Domain ◽  
Cilia Formation ◽  
Mother Centriole

Cilia formation is a multi-step process that starts with the docking of a vesicle at the distal part of the mother centriole. This step marks the conversion of the mother centriole into the basal body, from which axonemal microtubules extend to form the ciliary compartment. How vesicles are stably attached to the mother centriole to initiate ciliary membrane biogenesis is unknown. Here, we investigate the molecular role of the mother centriolar component Cep164 in ciliogenesis. We show that Cep164 was indispensable for the docking of vesicles at the mother centriole. Using biochemical and functional assays, we identified the components of the vesicular transport machinery, the GEF Rabin8 and the GTPase Rab8, as interacting partners of Cep164. We propose that Cep164 is targeted to the apical domain of the mother centriole to provide the molecular link between the mother centriole and the membrane biogenesis machinery that initiates cilia formation.

scholarly journals Pathogenic LRRK2 regulates ciliation probability upstream of tau tubulin kinase 2 via Rab10 and RILPL1 proteins

2021 ◽  
Vol 118 (10) ◽  
pp. e2005894118
Author(s):  
Yuriko Sobu ◽  
Paulina S. Wawro ◽  
Herschel S. Dhekne ◽  
Wondwossen M. Yeshaw ◽  
Suzanne R. Pfeffer
Keyword(s):  
Kinase Activity ◽  
Cell Types ◽  
Ips Cells ◽  
Serum Starvation ◽  
Critical Detail ◽  
Cilia Formation ◽  
Mother Centriole ◽  
Lrrk2 Kinase ◽  
Lrrk2 Kinase Activity ◽  
Protein Blocks

Mutations that activate LRRK2 protein kinase cause Parkinson's disease. We showed previously that Rab10 phosphorylation by LRRK2 enhances its binding to RILPL1, and together, these proteins block cilia formation in a variety of cell types, including patient derived iPS cells. We have used live-cell fluorescence microscopy to identify, more precisely, the effect of LRRK2 kinase activity on both the formation of cilia triggered by serum starvation and the loss of cilia seen upon serum readdition. LRRK2 activity decreases the overall probability of ciliation without changing the rates of cilia formation in R1441C LRRK2 MEF cells. Cilia loss in these cells is accompanied by ciliary decapitation, and kinase activity does not change the timing or frequency of decapitation or the rate of cilia loss but increases the percent of cilia that are lost upon serum addition. LRRK2 activity, or overexpression of RILPL1 protein, blocks release of CP110 from the mother centriole, a step normally required for early ciliogenesis; LRRK2 blockade of CP110 uncapping requires Rab10 and RILPL1 proteins and is due to failure to recruit TTBK2, a kinase needed for CP110 release. In contrast, deciliation probability does not change in cells lacking Rab10 or RILPL1 and relies on a distinct LRRK2 pathway. These experiments provide critical detail to our understanding of the cellular consequences of pathogenic LRRK2 mutation and indicate that LRRK2 blocks ciliogenesis upstream of TTBK2 and enhances the deciliation process in response to serum addition.

scholarly journals A centriole's subdistal appendages: contributions to cell division, ciliogenesis and differentiation

Open Biology ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 200399
Author(s):  
Nicole A. Hall ◽  
Heidi Hehnly
Keyword(s):  
Cell Division ◽  
Cell Differentiation ◽  
Final Stage ◽  
Eukaryotic Species ◽  
Chromosome Alignment ◽  
Cilia Formation ◽  
Mother Centriole ◽  
Pericentriolar Material ◽  
Daughter Centriole

The centrosome is a highly conserved structure composed of two centrioles surrounded by pericentriolar material. The mother, and inherently older, centriole has distal and subdistal appendages, whereas the daughter centriole is devoid of these appendage structures. Both appendages have been primarily linked to functions in cilia formation. However, subdistal appendages present with a variety of potential functions that include spindle placement, chromosome alignment, the final stage of cell division (abscission) and potentially cell differentiation. Subdistal appendages are particularly interesting in that they do not always display a conserved ninefold symmetry in appendage organization on the mother centriole across eukaryotic species, unlike distal appendages. In this review, we aim to differentiate both the morphology and role of the distal and subdistal appendages, with a particular focus on subdistal appendages.

scholarly journals Analysis of LRRC45 indicates cooperative functions of distal appendages at early steps of ciliogenesis

2017 ◽  
Author(s):  
Bahtiyar Kurtulmus ◽  
Cheng Yuan ◽  
Jakob Schuy ◽  
Annett Neuner ◽  
Shoji Hata ◽  
...  
Keyword(s):  
Stem Cells ◽  
Basal Body ◽  
Tissue Homeostasis ◽  
The Core ◽  
Cilia Formation ◽  
Mother Centriole ◽  
Appendage Formation ◽  
Motile Cilia

AbstractCilia perform essential signalling functions during development and tissue homeostasis. Ciliary malfunction causes a variety of diseases, named ciliopathies. The key role that the mother centriole plays in cilia formation can be attributed to appendage proteins that associate exclusively with the mother centriole. The distal appendages form a platform that docks early ciliary vesicles and removes CP110/Cep97 inhibitory complexes from the mother centriole. Here, we analysed the role played by LRRC45 in appendage formation and ciliogenesis. We show that the core appendage proteins Cep83 and SCLT1 recruit LRRC45 to the mother centriole. Once there LRRC45 recruits FBF1. The association of LRRC45 with the basal body of primary and motile cilia in differentiated and stem cells reveals a broad function in ciliogenesis. In contrast to the appendage components Cep164 and Cep123, LRRC45 was neither essential for docking of early ciliary vesicles nor for removal of CP110. Rather, LRRC45 promotes cilia biogenesis in CP110-uncapped centrioles by organising centriolar satellites and promoting the docking of Rab8 GTPase-positive vesicles. We propose that, instead of acting solely as a platform to recruit early vesicles, centriole appendages form discrete scaffolds of cooperating proteins that execute specific functions that promote the initial steps of ciliogenesis.

scholarly journals The OFD1 protein is a novel player in selective autophagy: another tile to the cilia/autophagy puzzle

Cell Stress ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 33-36
Author(s):  
Manuela Morleo ◽  
Brunella Franco
Keyword(s):  
Basal Body ◽  
Primary Cilia ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Direct Role ◽  
Body Protein ◽  
Selective Autophagy ◽  
Mother Centriole ◽  
The Impact

The autophagy-lysosomal pathway is one of the main degradative routes which cells use to balance sources of energy. A number of proteins orchestrate the formation of autophagosomes, membranous organelles instrumental in autophagy. Selective autophagy, involving the recognition and removal of specific targets, is mediated by autophagy receptors, which recognize cargos and the autophagosomal membrane protein LC3 for lysosomal degradation. Recently, bidirectional crosstalk has emerged between autophagy and primary cilia, microtubule-based sensory organelles extending from cells and anchored by the basal body, derived from the mother centriole of the centrosome. The molecular mechanisms underlying the direct role of autophagic proteins in cilia biology and, conversely, the impact of this organelle in autophagy remains elusive. Recently, we uncovered the molecular mechanism by which the centrosomal/basal body protein OFD1 controls the LC3-mediated autophagic cascade. In particular, we demonstrated that OFD1 acts as a selective autophagy receptor by regulating the turnover of unc-51-like kinase (ULK1) complex, which plays a crucial role in the initiation steps of autophagosome biogenesis. Moreover, we showed that patients with a genetic condition caused by mutations in OFD1 and associated with cilia dysfunction, display excessive autophagy and we demonstrated that autophagy inhibition significantly ameliorates the renal cystic phenotype in a conditional mouse model recapitulating the features of the disease (Morleo et al. 2020, EMBO J, doi: 10.15252/embj.2020105120). We speculate that abnormal autophagy may underlie some of the clinical manifestations observed in the disorders ascribed to cilia dysfunction.

scholarly journals RABL2 interacts with the intraflagellar transport-B complex and CEP19 and participates in ciliary assembly

2017 ◽  
Vol 28 (12) ◽  
pp. 1652-1666 ◽  
Author(s):  
Yuya Nishijima ◽  
Yohei Hagiya ◽  
Tomohiro Kubo ◽  
Ryota Takei ◽  
Yohei Katoh ◽  
...  
Keyword(s):  
Basal Body ◽  
Intraflagellar Transport ◽  
Bound State ◽  
Dependent Manner ◽  
Centrosomal Protein ◽  
Mother Centriole ◽  
Flagellar Assembly ◽  
Exogenous Expression ◽  
And Function

Proteins localized to the basal body and the centrosome play crucial roles in ciliary assembly and function. Although RABL2 and CEP19 are conserved in ciliated organisms and have been implicated in ciliary/flagellar functions, their roles are poorly understood. Here we show that RABL2 interacts with CEP19 and is recruited to the mother centriole and basal body in a CEP19-dependent manner and that CEP19 is recruited to the centriole probably via its binding to the centrosomal protein FGFR1OP. Disruption of the RABL2 gene in Chlamydomonas reinhardtii results in the nonflagellated phenotype, suggesting a crucial role of RABL2 in ciliary/flagellar assembly. We also show that RABL2 interacts, in its GTP-bound state, with the intraflagellar transport (IFT)-B complex via the IFT74–IFT81 heterodimer and that the interaction is disrupted by a mutation found in male infertile mice (Mot mice) with a sperm flagella motility defect. Intriguingly, RABL2 binds to CEP19 and the IFT74–IFT81 heterodimer in a mutually exclusive manner. Furthermore, exogenous expression of the GDP-locked or Mot-type RABL2 mutant in human cells results in mild defects in ciliary assembly. These results indicate that RABL2 localized to the basal body plays crucial roles in ciliary/flagellar assembly via its interaction with the IFT-B complex.

scholarly journals The Centriole Cartwheel Protein SAS-6 in Trypanosoma brucei Is Required for Probasal Body Biogenesis and Flagellum Assembly

2015 ◽  
Vol 14 (9) ◽  
pp. 898-907 ◽  
Author(s):  
Huiqing Hu ◽  
Yi Liu ◽  
Qing Zhou ◽  
Sara Siegel ◽  
Ziyin Li
Keyword(s):  
Cell Cycle ◽  
Rna Interference ◽  
Trypanosoma Brucei ◽  
Basal Body ◽  
Essential Role ◽  
Microtubule Organizing Center ◽  
Content Type ◽  
Evolutionarily Conserved ◽  
Organizing Center

ABSTRACT The centriole in eukaryotes functions as the cell's microtubule-organizing center (MTOC) to nucleate spindle assembly, and its biogenesis requires an evolutionarily conserved protein, SAS-6, which assembles the centriole cartwheel. Trypanosoma brucei , an early branching protozoan, possesses the basal body as its MTOC to nucleate flagellum biogenesis. However, little is known about the components of the basal body and their roles in basal body biogenesis and flagellum assembly. Here, we report that the T. brucei SAS-6 homolog, TbSAS-6, is localized to the mature basal body and the probasal body throughout the cell cycle. RNA interference (RNAi) of TbSAS-6 inhibited probasal body biogenesis, compromised flagellum assembly, and caused cytokinesis arrest. Surprisingly, overexpression of TbSAS-6 in T. brucei also impaired probasal body duplication and flagellum assembly, contrary to SAS-6 overexpression in humans, which produces supernumerary centrioles. Furthermore, we showed that depletion of T. brucei Polo-like kinase, TbPLK, or inhibition of TbPLK activity did not abolish TbSAS-6 localization to the basal body, in contrast to the essential role of Polo-like kinase in recruiting SAS-6 to centrioles in animals. Altogether, these results identified the essential role of TbSAS-6 in probasal body biogenesis and flagellum assembly and suggest the presence of a TbPLK-independent pathway governing basal body duplication in T. brucei .

scholarly journals Shootin1: a protein involved in the organization of an asymmetric signal for neuronal polarization

2006 ◽  
Vol 175 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Michinori Toriyama ◽  
Tadayuki Shimada ◽  
Ki Bum Kim ◽  
Mari Mitsuba ◽  
Eiko Nomura ◽  
...  
Keyword(s):  
Rna Interference ◽  
Hippocampal Neurons ◽  
Kinase Activity ◽  
Growth Cones ◽  
Intracellular Signals ◽  
Phosphoinositide 3 Kinase ◽  
Neuronal Polarization ◽  
Novel Protein

Neurons have the remarkable ability to polarize even in symmetrical in vitro environments. Although recent studies have shown that asymmetric intracellular signals can induce neuronal polarization, it remains unclear how these polarized signals are organized without asymmetric cues. We describe a novel protein, named shootin1, that became up-regulated during polarization of hippocampal neurons and began fluctuating accumulation among multiple neurites. Eventually, shootin1 accumulated asymmetrically in a single neurite, which led to axon induction for polarization. Disturbing the asymmetric organization of shootin1 by excess shootin1 disrupted polarization, whereas repressing shootin1 expression inhibited polarization. Overexpression and RNA interference data suggest that shootin1 is required for spatially localized phosphoinositide-3-kinase activity. Shootin1 was transported anterogradely to the growth cones and diffused back to the soma; inhibiting this transport prevented its asymmetric accumulation in neurons. We propose that shootin1 is involved in the generation of internal asymmetric signals required for neuronal polarization.

Sign in / Sign up

Export Citation Format

Share Document