scholarly journals Faculty Opinions recommendation of Shulin packages axonemal outer dynein arms for ciliary targeting.

Author(s):  
Ahmet Yildiz
Keyword(s):  
Author(s):  
George Price ◽  
Lizardo Cerezo

Ultrastructural defects of ciliary structure have been known to cause recurrent sino-respiratory infection concurrent with Kartagener's syndrome. (1,2,3) These defects are also known to cause infertility in both males and females. (4) Overall, the defects are defined as the Immotile, or Dyskinetic Cilia Syndrome (DCS). Several ultrastructural findings have been described, including decreased number of cilia, multidirection orientation, fused and compound cilia, membrane blebs, excess matrix in the axoneme, missing outer tubular doublets, translocated doublets, defective radial spokes and dynein arms. A rare but noteworthy ultrastructural finding in DCS is the predominance of microvilli-like structures on the luminal surface of the respiratory epithelium. (5,6) These permanent surface modifications of the apical respiratory epithelium no longer resemble cilia but reflect the ultrastructure of stereocilia, similar to that found in the epidydimal epithelium. Like microvilli, stereocilia are devoid of microtubular ultrastructure in comparison with true cilia.


Author(s):  
P. Satir ◽  
J. Wais-Steder ◽  
J. Avolio
Keyword(s):  

In 1977, Sale and Satir showed that active microtubule sliding in trypsin-treated Tetrahymena axonemes is always of a single polarity. If the doublet bearing active arms is labelled N, by convention, the doublet that is pushed by those arms is N+l. In active sliding in trypsin-treated axonemes doublet N+l is always displaced tipwards with respect to N. Several different configurations of the dynein arms have been described. These include: (1) an extended configuration, where the dynein arms are tilted about 40° towards the base of the axoneme and are long enough to span the space between doublets N and Ntl completely (2) a standard, unattached image, such as is usually seen in thin section. In this configuration, the arms do not span the interdoublet gap. (3) the rigor image, where the arms always bridge the gap. This differs from the extended configuration because tilt is often absent, so that the arms often lie normal to doublets N and N+l.


Science ◽  
2021 ◽  
Vol 371 (6525) ◽  
pp. eabd4914
Author(s):  
Sudarshan Gadadhar ◽  
Gonzalo Alvarez Viar ◽  
Jan Niklas Hansen ◽  
An Gong ◽  
Aleksandr Kostarev ◽  
...  

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.


2002 ◽  
Vol 42 (supplement2) ◽  
pp. S85
Author(s):  
K. Wakabayashi ◽  
M. Hayashi ◽  
J. Usukura ◽  
R. Kamiya
Keyword(s):  

1980 ◽  
Vol 89 (1) ◽  
pp. 81-83 ◽  
Author(s):  
Fred S. Herzon ◽  
Shirley Murphy

Kartagener's syndrome has been found to be associated with the immotile cilia syndrome (lack of dynein arms and defective radial spokes in cilia). The ultrastructure of cilia of a child with Kartagener's syndrome was examined and found to be within normal limits. The implications of this are discussed.


2009 ◽  
Vol 20 (13) ◽  
pp. 3055-3063 ◽  
Author(s):  
Raqual Bower ◽  
Kristyn VanderWaal ◽  
Eileen O'Toole ◽  
Laura Fox ◽  
Catherine Perrone ◽  
...  

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.


1973 ◽  
Vol 12 (2) ◽  
pp. 345-367
Author(s):  
R. W. LINCK

Gill cilia and sperm flagella from the lamellibranch mollusc Aequipecten irradians were compared with respect to their ultrastructures and adenosinetriphosphatase activities. Cilia were isolated from excised gills using 3 different solutions: twice-concentrated seawater, 10 % ethanol-10 mM CaCl2 and 60% glycerol. In each case deciliation occurs by the severance of the cilium at the junction of the transition zone and the basal body, and in each case the ciliary ultrastructure is maintained. Sperm flagella were purified by mechanical decapitation. Cilia and sperm flagella have similar fine structures, except that the matrix of the cilia contains substantially more electron-dense material than that of flagella. The ATPase activity of purified cilia is approximately 0.09,µmol P1/min/mg protein; that of flagella is 0.13. Ciliary and flagellar axonemes were prepared by repeated extraction of the membranes with 1% Triton X-100. Ciliary axonemes maintain their 9 + 2 cylindrical orientation, whereas flagellar axonemes often appear as opened or fragmented arrays of the 9 + 2 structure, due to the partial breakdown of the flagellar nexin fibres. A-subfibre arms which were obvious in whole organelles are rarely seen in axoneme preparations. Again the ciliary matrix is considerably more amorphous than in flagellar axonemes. The ATPase activities of ciliary and flagellar axonemes are 0.13 and 0.12 µmol P1/min/mg protein respectively; however, activities of ciliary axonemes may vary by a factor of 2, depending on the method of isolation. The difficulty in observing A-subfibre arms in cross-sections of ciliary and flagellar axonemes is discussed in terms of random, non-reinforcing arrangements of the dynein arms.


2018 ◽  
Vol 11 (9) ◽  
pp. 770-780 ◽  
Author(s):  
Guang Liu ◽  
Limei Wang ◽  
Junmin Pan

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.


1977 ◽  
Vol 73 (1) ◽  
pp. 182-192 ◽  
Author(s):  
K Ogawa ◽  
D J Asai ◽  
C J Brokaw

Effects of an antiserum against native dynein 1 from sperm flagella of the sea urchin Strongylocentrotus purpuratus were compared with effects of an antiserum previously obtained against an ATPase-active tryptic fragment (fragment 1A) of dynein 1 from sperm flagella of the sea urchin, Anthocidaris crassispina. Both antisera precipitate dynein 1 and do not precipitate dynein 2. Only the fragment 1A antiserum precipitates fragment 1A and produces a measurable inhibition of dynein 1 ATPase activity. Both antisera inhibit the movement and the movement-coupled ATP dephosphorylation of reactivated spermatozoa. The inhibition of movement by the antiserum against dynein 1 is much less than by the antiserum against fragment 1A, suggesting that a specific interference with the active ATPase site may be required for effective inhibition of movement. Both antisera reduce the bend angle as well as the beat frequency of reactivated S. purpuratus spermatozoa, suggesting that the bend angle may depend on the activity of the dynein arms which generate active sliding.


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