Analyses of functional domains within the PF6 protein of the central apparatus reveal a role for PF6 sub-complex members in regulating flagellar beat frequency.

Numerous studies have indicated that each of the seven projections associated with the central pair of microtubules plays a distinct role in regulating eukaryotic ciliary/flagellar motility. Mutants which lack specific projections have distinct motility phenotypes. For example, Chlamydomonas pf6 mutants lack the C1a projection and have twitchy, non-beating flagella.