title: Dynamic curvature regulation accounts for the symmetric and asymmetric beats of Chlamydomonas flagella.
abstract: Cilia and flagella are model systems for studying how mechanical forces control morphology. The periodic bending motion of cilia and flagella is thought to arise from mechanical feedback: dynein motors generate sliding forces that bend the flagellum, and bending leads to deformations and stresses, which feed back and regulate the motors. Three alternative feedback mechanisms have been proposed: regulation by the sliding forces, regulation by the curvature of the flagellum, and regulation by the normal forces that deform the cross-section of the flagellum. In this work, we combined theoretical and experimental approaches to show that the curvature control mechanism is the one that accords best with the bending waveforms of Chlamydomonas flagella. We make the surprising prediction that the motors respond to the time derivative of curvature, rather than curvature itself, hinting at an adaptation mechanism controlling the flagellar beat.
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.
authors.forename: Pablo
authors.initials: P
authors.lastname: Sartori
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.
authors.forename: Veikko F
authors.initials: VF
authors.lastname: Geyer
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Scholich
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.
authors.forename: Frank
authors.identifier: 0000-0003-4731-9185
authors.initials: F
authors.lastname: Jülicher
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.
authors.forename: Jonathon
authors.identifier: 0000-0003-0086-1196
authors.initials: J
authors.lastname: Howard
mesh_terms: D002696:Chlamydomonas / Q000502:physiology*; D004398:Dyneins / Q000378:metabolism; D025461:Feedback, Physiological; D005407:Flagella / Q000502:physiology*; D008954:Models, Biological; D009068:Movement
chemical_list: D004398:Dyneins
keywords: Chlamydomonas; adaptation; axoneme; biophysics; cell biology; cilia and flagella; dynein; molecular motors; structural biology