EMD-20341
The Nexin-dynein Regulatory Complex (N-DRC) from the cryo-electron tomography and subtomographic average of isolated Chlamydomonas SNAP-DRC4 axonemes, labeled with streptavidin-nanogold
EMD-20341
Subtomogram averaging35.0 Å
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Map released: 06/11/2019
Last modified: 27/11/2019
Sample Organism:
Chlamydomonas reinhardtii
Sample: The nexin-dynein regulatory complex averaged from Chlamydomonas SNAP-DRC4 axoneme, labeled with streptavidin-nanogold
Deposition Authors: Gui L, Song K, Tritschler D, Bower R, Yan S, Dai A, Augspurger K, Sakizadeh J, Grzemska M, Ni T, Porter ME, Nicastro D
Sample: The nexin-dynein regulatory complex averaged from Chlamydomonas SNAP-DRC4 axoneme, labeled with streptavidin-nanogold
Deposition Authors: Gui L, Song K, Tritschler D, Bower R, Yan S, Dai A, Augspurger K, Sakizadeh J, Grzemska M, Ni T, Porter ME, Nicastro D
Scaffold subunits support associated subunit assembly in theChlamydomonasciliary nexin-dynein regulatory complex.
Gui L
,
Song K,
Tritschler D,
Bower R,
Yan S,
Dai A,
Augspurger K
,
Sakizadeh J,
Grzemska M
,
Ni T,
Porter ME,
Nicastro D
(2019) PNAS , 116 , 23152 - 23162
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(2019) PNAS , 116 , 23152 - 23162
Abstract:
The nexin-dynein regulatory complex (N-DRC) in motile cilia and flagella functions as a linker between neighboring doublet microtubules, acts to stabilize the axonemal core structure, and serves as a central hub for the regulation of ciliary motility. Although the N-DRC has been studied extensively using genetic, biochemical, and structural approaches, the precise arrangement of the 11 (or more) N-DRC subunits remains unknown. Here, using cryo-electron tomography, we have compared the structure of Chlamydomonas wild-type flagella to that of strains with specific DRC subunit deletions or rescued strains with tagged DRC subunits. Our results show that DRC7 is a central linker subunit that helps connect the N-DRC to the outer dynein arms. DRC11 is required for the assembly of DRC8, and DRC8/11 form a subcomplex in the proximal lobe of the linker domain that is required to form stable contacts to the neighboring B-tubule. Gold labeling of tagged subunits determines the precise locations of the previously ambiguous N terminus of DRC4 and C terminus of DRC5. DRC4 is now shown to contribute to the core scaffold of the N-DRC. Our results reveal the overall architecture of N-DRC, with the 3 subunits DRC1/2/4 forming a core complex that serves as the scaffold for the assembly of the "functional subunits," namely DRC3/5-8/11. These findings shed light on N-DRC assembly and its role in regulating flagellar beating.
The nexin-dynein regulatory complex (N-DRC) in motile cilia and flagella functions as a linker between neighboring doublet microtubules, acts to stabilize the axonemal core structure, and serves as a central hub for the regulation of ciliary motility. Although the N-DRC has been studied extensively using genetic, biochemical, and structural approaches, the precise arrangement of the 11 (or more) N-DRC subunits remains unknown. Here, using cryo-electron tomography, we have compared the structure of Chlamydomonas wild-type flagella to that of strains with specific DRC subunit deletions or rescued strains with tagged DRC subunits. Our results show that DRC7 is a central linker subunit that helps connect the N-DRC to the outer dynein arms. DRC11 is required for the assembly of DRC8, and DRC8/11 form a subcomplex in the proximal lobe of the linker domain that is required to form stable contacts to the neighboring B-tubule. Gold labeling of tagged subunits determines the precise locations of the previously ambiguous N terminus of DRC4 and C terminus of DRC5. DRC4 is now shown to contribute to the core scaffold of the N-DRC. Our results reveal the overall architecture of N-DRC, with the 3 subunits DRC1/2/4 forming a core complex that serves as the scaffold for the assembly of the "functional subunits," namely DRC3/5-8/11. These findings shed light on N-DRC assembly and its role in regulating flagellar beating.