Primary cilia mediate specific neuron-glia attachments in C. elegans through the secreted protein BUG-1.

BUG-1 is required for URX and BAG sensory neurons in Caenorhabditis elegans to attach their primary cilia to the ILsoL/R glial partner, enabling normal ciliary calcium signaling.

• Why it matters: Neuronal cilia-glia attachments in mammals are known but their formation and functional roles are unclear, and cilia defects cause severe neurological disorders.
• What they did: A genetic screen in Caenorhabditis elegans mapped a stereotyped cilia-glia attachment between URX/BAG cilia and ILsoL/R, testing BUG-1 localization and attachment dependence.
• The result: Without BUG-1, cilia remain but always fail to attach; URX lacks activity-dependent remodeling, and BAG shows reduced stimulus-evoked calcium entry and impaired calcium clearance.