Microstructure-Based Modeling of Primary Cilia Mechanics.

Area of Science:

• Cell Biology
• Biophysics
• Mechanobiology

Background:

• Primary cilia are crucial mechanosensing organelles, translating mechanical stimuli into cellular signals via transmembrane proteins.
• Existing models often conflate structural and sensing components, potentially misinterpreting mechanotransduction mechanisms.

Approach:

• Developed a novel microstructure-based primary cilium model distinguishing microtubule doublets and cilium membrane.
• Utilized refined analytical solutions and finite element simulations to model microtubule bending and cilium membrane stress.
• Integrated cryogenic electron tomography imaging data to create an imaging-informed computational model.

Key Points:

• Microtubule doublets exhibit significant twisting during cilium bending, and mechanical properties are deformation-dependent.
• Cilium membrane experiences local bending stress, particularly near the base, challenging the pure tension/compression model.
• Microtubule doublet length distribution, not just overall cilium length, is the primary determinant of bending stiffness.

Conclusions:

• Primary cilia mechanosensing may rely more on membrane curvature changes than membrane stretching.
• This challenges traditional models and highlights the importance of detailed structural components in mechanotransduction.
• The findings expand our understanding of cellular responses to mechanical stimuli.