Understanding the importance of cytoskeletal connections in cilia coordination

Cilia are hair-like organelles on cell surfaces that beat to generate flows essential for many cellular functions, ranging from mucus clearance in humans to locomotion in unicellular organisms. Cilia form arrays of thousands of filaments arranged in highly organized spatial patterns, and coordinate temporally to form wave-like patterns known as metachronal waves. However, the mechanisms behind this cilia coordination remain elusive. In cells, cilia are interconnected by various cytoskeletal protein networks. We use Paramecium, a unicellular organism that swims using thousands of cilia on its surface, to investigate the role of these networks in cilia coordination. We deplete different cytoskeletal networks linking cilia, disrupting both local protein connections between neighboring cilia and a global network spanning the entire array. We measure both the changes in cilia organization and cell dynamics, including the swimming trajectories and cilia coordination. We observed that especially local connections are crucial for cell dynamics. Disrupting local connections leads to a disorganized cilia array and altered swimming behavior, highlighting their role in maintaining coordination. In contrast, depleting the global network did not significantly affect cilia organization or cell dynamics. These insights advance our understanding of cilia coordination, establishing clear connections between the structure of the cilia array and the resulting cell dynamics.