scholarly journals Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM

2019 ◽  
Author(s):  
Wei Zheng ◽  
Fan Li ◽  
Zhanyu Ding ◽  
Hao Liu ◽  
Lei Zhu ◽  
...  
Keyword(s):  
Interaction Network ◽  
Core Complex ◽  
Central Pair ◽  
Radial Spoke ◽  
Ciliary Motility ◽  
Axonemal Dynein ◽  
Compact Body ◽  
Dynein Arms

AbstractThe radial spoke (RS) transmits mechanochemical signals from the central pair apparatus (CP) to axonemal dynein arms to coordinate ciliary motility. The RS head, directly contacting with CP, differs dramatically in morphology between protozoan and mammal. Here we show the murine RS head is compositionally distinct from the Chlamydomonas one. Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a whose orthologue exists in the Chlamydomonas RS head. We present the unprecedented cryo-EM structure of RS head core complex at 4.5-Å resolution and identified the subunit location and their interaction network. In this complex, Rsph3b, Rsph4a, and Rsph9 forms a compact body with Rsph4a serving possibly as an assembly scaffold and Rsph3b in a location that might link the head with stalk. Interestingly, two Rsph1 subunits constitute the two stretching-arms possibly for optimized RS-CP interaction. We also propose a sawtooth model for the RS-CP interaction. Our study suggests that the RS head experiences profound remodeling to probably comply with both structural and functional alterations of the axoneme during evolution.

scholarly journals Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM

2021 ◽  
Vol 118 (4) ◽  
pp. e2021180118
Author(s):  
Wei Zheng ◽  
Fan Li ◽  
Zhanyu Ding ◽  
Hao Liu ◽  
Lei Zhu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Brake Pad ◽  
Core Complex ◽  
Central Pair ◽  
Radial Spoke ◽  
The Core ◽  
Cryo Electron Microscopy ◽  
Compact Body ◽  
Β Sheets ◽  
Cilia And Flagella

The radial spoke (RS) heads of motile cilia and flagella contact projections of the central pair (CP) apparatus to coordinate motility, but the morphology is distinct for protozoa and metazoa. Here we show the murine RS head is compositionally distinct from that ofChlamydomonas. Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a and Rsph10b, whose orthologs exist in the protozoan RS head. We resolve its cryo-electron microscopy (cryo-EM) structure at 3.2-Å resolution. Our atomic model further reveals a twofold symmetric brake pad-shaped structure, in which Rsph4a and Rsph9 form a compact body extended laterally with two long arms of twisted Rsph1 β-sheets and potentially connected dorsally via Rsph3b to the RS stalk. Furthermore, our modeling suggests that the core complex contacts the periodic CP projections either rigidly through its tooth-shaped Rsph4a regions or elastically through both arms for optimized RS–CP interactions and mechanosignal transduction.

scholarly journals The CSC proteins FAP61 and FAP251 build the basal substructures of radial spoke 3 in cilia

2015 ◽  
Vol 26 (8) ◽  
pp. 1463-1475 ◽  
Author(s):  
Paulina Urbanska ◽  
Kangkang Song ◽  
Ewa Joachimiak ◽  
Lucja Krzemien-Ojak ◽  
Piotr Koprowski ◽  
...  
Keyword(s):  
Radial Spoke ◽  
Ciliary Motility ◽  
Distinct Structure ◽  
Radial Spokes ◽  
Dynein Arms ◽  
Motile Cilia ◽  
The Individual ◽  
And Function

Dynein motors and regulatory complexes repeat every 96 nm along the length of motile cilia. Each repeat contains three radial spokes, RS1, RS2, and RS3, which transduct signals between the central microtubules and dynein arms. Each radial spoke has a distinct structure, but little is known about the mechanisms of assembly and function of the individual radial spokes. In Chlamydomonas, calmodulin and spoke-associated complex (CSC) is composed of FAP61, FAP91, and FAP251 and has been linked to the base of RS2 and RS3. We show that in Tetrahymena, loss of either FAP61 or FAP251 reduces cell swimming and affects the ciliary waveform and that RS3 is either missing or incomplete, whereas RS1 and RS2 are unaffected. Specifically, FAP251-null cilia lack an arch-like density at the RS3 base, whereas FAP61-null cilia lack an adjacent portion of the RS3 stem region. This suggests that the CSC proteins are crucial for stable and functional assembly of RS3 and that RS3 and the CSC are important for ciliary motility.

scholarly journals FAP206 is a microtubule-docking adapter for ciliary radial spoke 2 and dynein c

2015 ◽  
Vol 26 (4) ◽  
pp. 696-710 ◽  
Author(s):  
Krishna Kumar Vasudevan ◽  
Kangkang Song ◽  
Lea M. Alford ◽  
Winfield S. Sale ◽  
Erin E. Dymek ◽  
...  
Keyword(s):  
Cell Motility ◽  
Electron Tomography ◽  
Macromolecular Complexes ◽  
Radial Spoke ◽  
Ciliary Motility ◽  
Cryo Electron Tomography ◽  
Ciliary Protein ◽  
Radial Spokes ◽  
Dynein Arms

Radial spokes are conserved macromolecular complexes that are essential for ciliary motility. A triplet of three radial spokes, RS1, RS2, and RS3, repeats every 96 nm along the doublet microtubules. Each spoke has a distinct base that docks to the doublet and is linked to different inner dynein arms. Little is known about the assembly and functions of individual radial spokes. A knockout of the conserved ciliary protein FAP206 in the ciliate Tetrahymena resulted in slow cell motility. Cryo–electron tomography showed that in the absence of FAP206, the 96-nm repeats lacked RS2 and dynein c. Occasionally, RS2 assembled but lacked both the front prong of its microtubule base and dynein c, whose tail is attached to the front prong. Overexpressed GFP-FAP206 decorated nonciliary microtubules in vivo. Thus FAP206 is likely part of the front prong and docks RS2 and dynein c to the microtubule.

scholarly journals The I1 dynein-associated tether and tether head complex is a conserved regulator of ciliary motility

2018 ◽  
Vol 29 (9) ◽  
pp. 1048-1059 ◽  
Author(s):  
Gang Fu ◽  
Qian Wang ◽  
Nhan Phan ◽  
Paulina Urbanska ◽  
Ewa Joachimiak ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Regulatory Mechanisms ◽  
Ciliary Beating ◽  
Radial Spoke ◽  
Ciliary Motility ◽  
Dynein Motor ◽  
Axonemal Dynein ◽  
Motile Cilia ◽  
Mechanical Feedback

Motile cilia are essential for propelling cells and moving fluids across tissues. The activity of axonemal dynein motors must be precisely coordinated to generate ciliary motility, but their regulatory mechanisms are not well understood. The tether and tether head (T/TH) complex was hypothesized to provide mechanical feedback during ciliary beating because it links the motor domains of the regulatory I1 dynein to the ciliary doublet microtubule. Combining genetic and biochemical approaches with cryoelectron tomography, we identified FAP44 and FAP43 (plus the algae-specific, FAP43-redundant FAP244) as T/TH components. WT-mutant comparisons revealed that the heterodimeric T/TH complex is required for the positional stability of the I1 dynein motor domains, stable anchoring of CK1 kinase, and proper phosphorylation of the regulatory IC138-subunit. T/TH also interacts with inner dynein arm d and radial spoke 3, another important motility regulator. The T/TH complex is a conserved regulator of I1 dynein and plays an important role in the signaling pathway that is critical for normal ciliary motility.

scholarly journals Mutations in the "dynein regulatory complex" alter the ATP-insensitive binding sites for inner arm dyneins in Chlamydomonas axonemes.

1994 ◽  
Vol 125 (5) ◽  
pp. 1109-1117 ◽  
Author(s):  
G Piperno ◽  
K Mead ◽  
M LeDizet ◽  
A Moscatelli
Keyword(s):  
Molecular Weight ◽  
Binding Site ◽  
Binding Sites ◽  
Apparent Molecular Weight ◽  
Central Pair ◽  
Radial Spoke ◽  
Regulatory Complex ◽  
Dynein Arms

To understand mechanisms of regulation of dynein activity along and around the axoneme we further characterized the "dynein regulatory complex" (drc). The lack of some axonemal proteins, which together are referred to as drc, causes the suppression of flagellar paralysis of radial spoke and central pair mutants. The drc is also an adapter involved in the ATP-insensitive binding of I2 and I3 inner dynein arms to doublet microtubules. Evidence supporting these conclusions was obtained through analyses of five drc mutants: pf2, pf3, suppf3, suppf4, and suppf5. Axonemes from drc mutants lack part of I2 and I3 inner dynein arms as well as subsets of seven drc components (apparent molecular weight from 29,000 to 192,000). In the absence of ATP-Mg, dynein-depleted axonemes from the same mutants bind I2 and I3 inner arms at both ATP-sensitive and -insensitive sites. At ATP-insensitive sites, they bind I2 and I3 inner arms to an extent that depends on the drc defect. This evidence suggested to us that the drc forms one binding site for the I2 and I3 inner arms on the A part of doublet microtubules.

scholarly journals Tubulin glycylation controls axonemal dynein activity, flagellar beat, and male fertility

Science ◽  
2021 ◽  
Vol 371 (6525) ◽  
pp. eabd4914
Author(s):  
Sudarshan Gadadhar ◽  
Gonzalo Alvarez Viar ◽  
Jan Niklas Hansen ◽  
An Gong ◽  
Aleksandr Kostarev ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Male Fertility ◽  
Electron Tomography ◽  
Structural Basis ◽  
Cellular Functions ◽  
Flagellar Beat ◽  
Cryo Electron Tomography ◽  
Axonemal Dynein ◽  
Dynein Arms ◽  
Cilia And Flagella

Posttranslational modifications of the microtubule cytoskeleton have emerged as key regulators of cellular functions, and their perturbations have been linked to a growing number of human pathologies. Tubulin glycylation modifies microtubules specifically in cilia and flagella, but its functional and mechanistic roles remain unclear. In this study, we generated a mouse model entirely lacking tubulin glycylation. Male mice were subfertile owing to aberrant beat patterns of their sperm flagella, which impeded the straight swimming of sperm cells. Using cryo–electron tomography, we showed that lack of glycylation caused abnormal conformations of the dynein arms within sperm axonemes, providing the structural basis for the observed dysfunction. Our findings reveal the importance of microtubule glycylation for controlled flagellar beating, directional sperm swimming, and male fertility.

scholarly journals IC138 Defines a Subdomain at the Base of the I1 Dynein That Regulates Microtubule Sliding and Flagellar Motility

2009 ◽  
Vol 20 (13) ◽  
pp. 3055-3063 ◽  
Author(s):  
Raqual Bower ◽  
Kristyn VanderWaal ◽  
Eileen O'Toole ◽  
Laura Fox ◽  
Catherine Perrone ◽  
...  
Keyword(s):  
Double Mutant ◽  
Essential Role ◽  
Null Allele ◽  
Flagellar Motility ◽  
Wild Type ◽  
Gene Encoding ◽  
Radial Spoke ◽  
Mutant Strains ◽  
Dynein Arms ◽  
Image Averaging

To understand the mechanisms that regulate the assembly and activity of flagellar dyneins, we focused on the I1 inner arm dynein (dynein f) and a null allele, bop5-2, defective in the gene encoding the IC138 phosphoprotein subunit. I1 dynein assembles in bop5-2 axonemes but lacks at least four subunits: IC138, IC97, LC7b, and flagellar-associated protein (FAP) 120—defining a new I1 subcomplex. Electron microscopy and image averaging revealed a defect at the base of the I1 dynein, in between radial spoke 1 and the outer dynein arms. Microtubule sliding velocities also are reduced. Transformation with wild-type IC138 restores assembly of the IC138 subcomplex and rescues microtubule sliding. These observations suggest that the IC138 subcomplex is required to coordinate I1 motor activity. To further test this hypothesis, we analyzed microtubule sliding in radial spoke and double mutant strains. The results reveal an essential role for the IC138 subcomplex in the regulation of I1 activity by the radial spoke/phosphorylation pathway.

scholarly journals Chlamydomonas WDR92 in association with R2TP-like complex and multiple DNAAFs to regulate ciliary dynein preassembly

2018 ◽  
Vol 11 (9) ◽  
pp. 770-780 ◽  
Author(s):  
Guang Liu ◽  
Limei Wang ◽  
Junmin Pan
Keyword(s):  
Mass Spectrometry ◽  
Insertional Mutagenesis ◽  
The Other ◽  
Cytoplasmic Protein ◽  
Flagellar Motility ◽  
Heavy Chains ◽  
The Third ◽  
Axonemal Dynein ◽  
Dynein Arms ◽  
Dna Insertional Mutagenesis

Abstract The motility of cilia or eukaryotic flagella is powered by the axonemal dyneins, which are preassembled in the cytoplasm by proteins termed dynein arm assembly factors (DNAAFs) before being transported to and assembled on the ciliary axoneme. Here, we characterize the function of WDR92 in Chlamydomonas. Loss of WDR92, a cytoplasmic protein, in a mutant wdr92 generated by DNA insertional mutagenesis resulted in aflagellate cells or cells with stumpy or short flagella, disappearance of axonemal dynein arms, and diminishment of dynein arm heavy chains in the cytoplasm, suggesting that WDR92 is a DNAAF. Immunoprecipitation of WDR92 followed by mass spectrometry identified inner dynein arm heavy chains and multiple DNAAFs including RuvBL1, RPAP3, MOT48, ODA7, and DYX1C. The PIH1 domain-containing protein MOT48 formed a R2TP-like complex with RuvBL1/2 and RPAP3, while PF13, another PIH1 domain-containing protein with function in dynein preassembly, did not. Interestingly, the third PIH1 domain-containing protein TWI1 was not related to flagellar motility. WDR92 physically interacted with the R2TP-like complex and the other identified DNNAFs. Our data suggest that WDR92 functions in association with the HSP90 co-chaperone R2TP-like complex as well as linking other DNAAFs in dynein preassembly.

scholarly journals Pcdp1 is a central apparatus protein that binds Ca2+-calmodulin and regulates ciliary motility

2010 ◽  
Vol 189 (3) ◽  
pp. 601-612 ◽  
Author(s):  
Christen G. DiPetrillo ◽  
Elizabeth F. Smith
Keyword(s):  
Primary Ciliary Dyskinesia ◽  
Calcium Concentration ◽  
Beat Frequency ◽  
Calcium Sensor ◽  
Central Pair ◽  
Ciliary Motility ◽  
Significant Impairment ◽  
Central Apparatus ◽  
Cilia And Flagella ◽  
Ciliary Dyskinesia

For all motile eukaryotic cilia and flagella, beating is regulated by changes in intraciliary calcium concentration. Although the mechanism for calcium regulation is not understood, numerous studies have shown that calmodulin (CaM) is a key axonemal calcium sensor. Using anti-CaM antibodies and Chlamydomonas reinhardtii axonemal extracts, we precipitated a complex that includes four polypeptides and that specifically interacts with CaM in high [Ca2+]. One of the complex members, FAP221, is an orthologue of mammalian Pcdp1 (primary ciliary dyskinesia protein 1). Both FAP221 and mammalian Pcdp1 specifically bind CaM in high [Ca2+]. Reduced expression of Pcdp1 complex members in C. reinhardtii results in failure of the C1d central pair projection to assemble and significant impairment of motility including uncoordinated bends, severely reduced beat frequency, and altered waveforms. These combined results reveal that the central pair Pcdp1 (FAP221) complex is essential for control of ciliary motility.

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