Mechanisms of ciliary motility

An update

Peter Satir

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Ciliary motility is dependent upon dynein-driven sliding of microtubules. Attention has been focussed on the molecular biology and mechanochemistry of dynein, via techniques involving mutant analysis and in vitro motility measurements. In Chlamydomonas, Tetrahymena and Paramecium, the best studied protistan genera, the outer dynein arm is a compacted three-headed heterotrimeric bouquet. Every bouquet is identical, while each ATPase head of the bouquet is coded by a different dynein heavy (H) chain gene. One H chain (Paramecium α) binds a 29 kDa regulatory light chain whose phosphorylation increases the velocity of sliding of the dynein, which in turn increases ciliary beat frequency. At least seven different H chains within a 96 nm spoke group repeat form the inner dynein arms. The structural organization of the inner arms is complex, and several models have been proposed. The inner dynein arms evidently control bend formation. Their activity also changes upon phosphorylation or dephosphorylation, the signal for which is transduced via the spoke-central sheath complex and a dynein-regulatory complex that lies adjacent to the arms on the doublet. How inner and outer arms operate coordinately is not understood. The outer dynein arms have a strong attachment and force-producing phase that is very short (1%) compared to their cycle time. Only a few dynein steps probably occur per doublet during an effective stroke, which suggests that arm activity on an active doublet is stochastic. The orientation of the central pair within the axoneme determines the plane of bending, probably by dividing the doublets into active and inactive half axonemes, according to a switch point model. Computer reconstructions and analytical techniques such as finite element analysis are useful tools of exploring this model. Although many aspects of the mechanism of bend production and propagation still remain either undefined or controversial, a general outline is beginning to emerge.

Original languageEnglish (US)
Pages (from-to)267-272
Number of pages6
JournalEuropean Journal of Protistology
Volume34
Issue number3
StatePublished - 1998

Fingerprint

Dyneins
Paramecium
phosphorylation
computer techniques
Tetrahymena
finite element analysis
dephosphorylation
Chlamydomonas
stroke
molecular biology
microtubules
adenosinetriphosphatase
analytical methods
Axoneme
mutants
Phosphorylation
genes
Finite Element Analysis
Microtubules
Adenosine Triphosphatases

Keywords

  • Axoneme
  • Cilia
  • Dynein
  • Protistan motility

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Microbiology

Cite this

Mechanisms of ciliary motility : An update. / Satir, Peter.

In: European Journal of Protistology, Vol. 34, No. 3, 1998, p. 267-272.

Research output: Contribution to journalArticle

Satir, P 1998, 'Mechanisms of ciliary motility: An update', European Journal of Protistology, vol. 34, no. 3, pp. 267-272.
Satir, Peter. / Mechanisms of ciliary motility : An update. In: European Journal of Protistology. 1998 ; Vol. 34, No. 3. pp. 267-272.
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