Functionally significant central-pair rotation in a primitive eukaryotic flagellum

Area of Science:

• Cell Biology
• Biophysics
• Marine Biology

Background:

• Ciliary and flagellar movement relies on microtubule sliding within the axoneme.
• The precise control mechanisms coordinating this sliding for effective motion remain largely unknown.
• The central pair of microtubules is a potential component involved in this regulation.

Purpose of the Study:

• To investigate the role of the central pair of microtubules in flagellar movement.
• To understand the control mechanisms of ciliary and flagellar motion.
• To examine flagellar mechanics in the marine alga Micromonas pusilla.

Main Methods:

• Studied the uniflagellate marine alga Micromonas pusilla.
• Observed the central pair of microtubules in living M. pusilla flagella.
• Focused on flagella where central tubules extend beyond peripheral doublets for direct observation.

Main Results:

• The central pair of microtubules in M. pusilla flagella undergoes continuous, unidirectional rotation.
• This observed rotation was found to provide the motive force for cellular locomotion.
• Direct observation of the central pair during movement was enabled by its extended structure.

Conclusions:

• The rotation of the central pair of microtubules is a key mechanism driving flagellar propulsion.
• This finding offers new insights into the coordination of microtubule sliding for ciliary and flagellar motion.
• The central pair's rotational activity is crucial for the motility of Micromonas pusilla.