BBSome loss lets misplaced proteins travel inside worm cilia
Proteins normally kept outside cilia accumulated inside these cell-surface projections when worms lacked the BBSome protein complex. Peer-reviewed imaging experiments indicate that rapid diffusion was still largely blocked by the entrance barrier. The finding supports a separate cargo-selection step alongside the entrance gate, broadening the proposed explanation for how cilia maintain their protein composition.
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Misplaced proteins accumulated inside cilia
A protein complex helps regulate what enters cilia, the small projections on cell surfaces. In peer-reviewed experiments published on 25 October, worms lacking BBSome components accumulated proteins that normally remain outside these structures. The work used Caenorhabditis elegans, a small nematode widely used in biological research. Fluorescent markers revealed the altered distribution of several proteins, including ELMD-1, while comparisons between normal animals and genetic mutants separated possible routes into the cilium.[1]
The diffusion barrier remained largely functional
The researchers examined whether accumulation followed a failure of the entrance barrier. They bleached fluorescent signals and watched how quickly the fluorescence returned. Without the BBSome, the entrance barrier continued to restrict rapid diffusion, even though unwanted proteins were already inside the cilia. That finding supports an explanation involving how cargo is selected for transport, alongside the physical gate. The complex is associated with Bardet–Biedl syndrome, but the experiments concerned a basic cellular mechanism in worms.[1]
Some misplaced cargo travelled in both directions
Movement of some wrongly located proteins ran both ways along the cilia, at speeds matching the internal transport system. Measurements also placed a misplaced protein close to a transport component. The authors propose two control steps: selection of cargo, followed by passage through the ciliary gate. Contributions from defective removal remain possible, particularly later in development. How these processes operate in other organisms and cell types requires further investigation; human treatment effects were outside this experiment.[1]
