Cilia and flagella play essential roles in cell motility, sensing and development. These organelles have tightly controlled lengths, and the axoneme, which forms the core structure, has exceptionally high stability. This is despite being composed of microtubules that are often characterized as highly dynamic. To understand how ciliary tubulin contribute to stability, we develop a procedure to differentially extract tubulins from different components of axonemes purified from Chlamydomonas reinhardtii, and characterize their properties. We find that the microtubules support length stability by two distinct mechanisms: low dynamicity, and unusual stability of the protofilaments. The high stability of the protofilaments manifests itself in the formation of curved tip structures, up to a few microns long. These structures likely reflect intrinsic curvature of GTP or GDP·Pi tubulin and provide structural insights into the GTP-cap. Together, our study provides insights into growth, stability and the role of post-translational modifications of axonemal microtubules.
|State||Published - 1 Dec 2019|
Bibliographical noteFunding Information:
We thank Dr. Xinran Liu from the core center for cellular and molecular imaging at Yale for sample processing, sectioning and image acquisition, and Dr. Joel Nott from the protein facility at Iowa State University for the mass-spectrometry analysis. Special thanks to Dr. Sabyasachi Sutradhar for the great help with MATLAB and all The Howard lab members for fruitful discussion. Research reported in this publication was supported by a Cross-Disciplinary Fellowship from Human Frontier Science Program (LT000919/ 2015-C) and European Molecular Biology Organization long-term fellowship (ALTF 1424-2014) to RO, and National Institute of General Medicine Sciences of the National Institutes of Health under award number R01GM110386 to JH.
© 2019, The Author(s).