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Axonemal radial spokes: 3D structure, function and assembly.

Pigino G, Ishikawa T - Bioarchitecture (2012)

Bottom Line: Despite numerous biochemical, physiological and structural studies, the mechanism of the function of the radial spoke remains unclear.Detailed knowledge of the 3D structure of the RS protein complex is needed in order to understand how RS regulates dynein activity.Here we review the most important findings on the structure of the RS, including results of our recent cryo-electron tomographic analysis of the RS protein complex.

View Article: PubMed Central - PubMed

ABSTRACT
The radial spoke (RS) is a complex of at least 23 proteins that works as a mechanochemical transducer between the central-pair apparatus and the peripheral microtubule doublets in eukaryotic flagella and motile cilia. The RS contributes to the regulation of the activity of dynein motors, and thus to flagellar motility. Despite numerous biochemical, physiological and structural studies, the mechanism of the function of the radial spoke remains unclear. Detailed knowledge of the 3D structure of the RS protein complex is needed in order to understand how RS regulates dynein activity. Here we review the most important findings on the structure of the RS, including results of our recent cryo-electron tomographic analysis of the RS protein complex.

No MeSH data available.


Related in: MedlinePlus

Figure 1. Placement of the RSs in the Axoneme. (A) Scheme of the 9 + 2 axonemal structure, showing the placement of main axonemal components. Radial spokes (red), inner dynein arms (blue), outer dynein arms (turquoise), microtubules (black), N‐DRC (green), central pair complex (gray). (B) Surface renderings of tomographic reconstruction of a 96 nm repeat along one of the MTDs of Chlamydomonas. The microtubules are shown in gray, the rest of the color‐coding is according to (A). RS1, RS2, and RS3 stump (RS3S) are shown. Isoforms of inner arm dyneins are indicated. Dynein b/g is either dynein b or dynein g, but it has not been determined which of the two this dynein is. It is the same case for dynein g/b, a/d, d/a. (C) Side view seen from the proximal end showing RS2, IDA c, ODA, and the microtubule doublet. A, A‐microtubule; B, B‐microtubule. The dashed line indicates the dynein c tail connecting to the RS2 base. The red arrowheads show the binding of the bifurcated base of RS to the protofilaments A12 and A13 of the A‐microtubule. [(B) was modified from ©Pigino et al., 2011. Originally published in JCB. DOI: 10.1083/jcb.201106125].
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Figure 1: Figure 1. Placement of the RSs in the Axoneme. (A) Scheme of the 9 + 2 axonemal structure, showing the placement of main axonemal components. Radial spokes (red), inner dynein arms (blue), outer dynein arms (turquoise), microtubules (black), N‐DRC (green), central pair complex (gray). (B) Surface renderings of tomographic reconstruction of a 96 nm repeat along one of the MTDs of Chlamydomonas. The microtubules are shown in gray, the rest of the color‐coding is according to (A). RS1, RS2, and RS3 stump (RS3S) are shown. Isoforms of inner arm dyneins are indicated. Dynein b/g is either dynein b or dynein g, but it has not been determined which of the two this dynein is. It is the same case for dynein g/b, a/d, d/a. (C) Side view seen from the proximal end showing RS2, IDA c, ODA, and the microtubule doublet. A, A‐microtubule; B, B‐microtubule. The dashed line indicates the dynein c tail connecting to the RS2 base. The red arrowheads show the binding of the bifurcated base of RS to the protofilaments A12 and A13 of the A‐microtubule. [(B) was modified from ©Pigino et al., 2011. Originally published in JCB. DOI: 10.1083/jcb.201106125].

Mentions: Eukaryotic flagella and motile cilia share a common “9 + 2” structure, in which nine peripheral microtubule doublets (MTDs) surround the central‐pair of microtubules (CP) (Fig. 1A). The MTDs and CP are connected by radial spokes (RSs). Genetic, biochemical, and structural analysis indicate that the mechano‐chemical interaction between RSs and CP regulates the activity of dynein motors attached to the MTDs and thus controls the bending motion of the flagellum.


Axonemal radial spokes: 3D structure, function and assembly.

Pigino G, Ishikawa T - Bioarchitecture (2012)

Figure 1. Placement of the RSs in the Axoneme. (A) Scheme of the 9 + 2 axonemal structure, showing the placement of main axonemal components. Radial spokes (red), inner dynein arms (blue), outer dynein arms (turquoise), microtubules (black), N‐DRC (green), central pair complex (gray). (B) Surface renderings of tomographic reconstruction of a 96 nm repeat along one of the MTDs of Chlamydomonas. The microtubules are shown in gray, the rest of the color‐coding is according to (A). RS1, RS2, and RS3 stump (RS3S) are shown. Isoforms of inner arm dyneins are indicated. Dynein b/g is either dynein b or dynein g, but it has not been determined which of the two this dynein is. It is the same case for dynein g/b, a/d, d/a. (C) Side view seen from the proximal end showing RS2, IDA c, ODA, and the microtubule doublet. A, A‐microtubule; B, B‐microtubule. The dashed line indicates the dynein c tail connecting to the RS2 base. The red arrowheads show the binding of the bifurcated base of RS to the protofilaments A12 and A13 of the A‐microtubule. [(B) was modified from ©Pigino et al., 2011. Originally published in JCB. DOI: 10.1083/jcb.201106125].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3383722&req=5

Figure 1: Figure 1. Placement of the RSs in the Axoneme. (A) Scheme of the 9 + 2 axonemal structure, showing the placement of main axonemal components. Radial spokes (red), inner dynein arms (blue), outer dynein arms (turquoise), microtubules (black), N‐DRC (green), central pair complex (gray). (B) Surface renderings of tomographic reconstruction of a 96 nm repeat along one of the MTDs of Chlamydomonas. The microtubules are shown in gray, the rest of the color‐coding is according to (A). RS1, RS2, and RS3 stump (RS3S) are shown. Isoforms of inner arm dyneins are indicated. Dynein b/g is either dynein b or dynein g, but it has not been determined which of the two this dynein is. It is the same case for dynein g/b, a/d, d/a. (C) Side view seen from the proximal end showing RS2, IDA c, ODA, and the microtubule doublet. A, A‐microtubule; B, B‐microtubule. The dashed line indicates the dynein c tail connecting to the RS2 base. The red arrowheads show the binding of the bifurcated base of RS to the protofilaments A12 and A13 of the A‐microtubule. [(B) was modified from ©Pigino et al., 2011. Originally published in JCB. DOI: 10.1083/jcb.201106125].
Mentions: Eukaryotic flagella and motile cilia share a common “9 + 2” structure, in which nine peripheral microtubule doublets (MTDs) surround the central‐pair of microtubules (CP) (Fig. 1A). The MTDs and CP are connected by radial spokes (RSs). Genetic, biochemical, and structural analysis indicate that the mechano‐chemical interaction between RSs and CP regulates the activity of dynein motors attached to the MTDs and thus controls the bending motion of the flagellum.

Bottom Line: Despite numerous biochemical, physiological and structural studies, the mechanism of the function of the radial spoke remains unclear.Detailed knowledge of the 3D structure of the RS protein complex is needed in order to understand how RS regulates dynein activity.Here we review the most important findings on the structure of the RS, including results of our recent cryo-electron tomographic analysis of the RS protein complex.

View Article: PubMed Central - PubMed

ABSTRACT
The radial spoke (RS) is a complex of at least 23 proteins that works as a mechanochemical transducer between the central-pair apparatus and the peripheral microtubule doublets in eukaryotic flagella and motile cilia. The RS contributes to the regulation of the activity of dynein motors, and thus to flagellar motility. Despite numerous biochemical, physiological and structural studies, the mechanism of the function of the radial spoke remains unclear. Detailed knowledge of the 3D structure of the RS protein complex is needed in order to understand how RS regulates dynein activity. Here we review the most important findings on the structure of the RS, including results of our recent cryo-electron tomographic analysis of the RS protein complex.

No MeSH data available.


Related in: MedlinePlus