Tetrahymena as a model organism for cilia research

Cilia are evolutionarily conserved organelles essential for motility and signaling, and their dysfunction underlies a wide spectrum of human diseases. The ciliate Tetrahymena is a powerful model organism for dissecting ciliary biology due to its abundance of motile cilia, genetic tractability, and suitability for biochemical and structural analyses. This review highlights the biological and experimental advantages of Tetrahymena and summarizes key insights it has provided into ciliary structure and function. Studies in Tetrahymena have elucidated the organization of the axoneme and doublet microtubules, the architecture and roles of microtubule inner proteins, and the regulatory networks formed by nexin-dynein regulatory complex, radial spokes, the central pair, and intraflagellar transport machinery. In addition, work in this system has been instrumental in defining post-translational modifications of tubulin and their functional consequences. Beyond the axoneme, we discuss advances in understanding basal body organization, structure and assembly. Collectively, these contributions establish Tetrahymena as a foundational model for cilia research.