Flagellar central pair complexes are helical when extruded.

In many organisms, the central pairs (CPs) of 9+2 cilia and flagella spin. Mitchell and Nakatsugawa (page 709) now claim that this spinning is an effect, not a cause, of flagellar bend propagation.

Motile 9+2 cilia and flagella owe their whip-like movement to motors in the outside barrel of fused doublet microtubules, with motors anchored to one doublet pushing on a neighboring doublet. But the more enigmatic part of this structure is the CP. This doublet of microtubules is connected to the outside barrel via radial spokes that are thought to modulate motor action.

That modulation requires a constant relationship between a particular face of the CP and those microtubule motors that are active at any one time—which is where spinning and twisting come in. Looking at electron micrographs of wild-type Chlamydomonas, Mitchell and...

The Rockefeller University Press
2004
The Rockefeller University Press
2004
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