A Conserved Role for Girdin in Basal Body Positioning and Ciliogenesis

Primary cilia are ubiquitous sensory organelles that mediate diverse signaling pathways. Cilia position on the cell surface is determined by the location of the basal body (BB) that templates the cilium. The mechanisms that regulate BB positioning in the context of ciliogenesis are largely unknown. Here we show that the conserved signaling and scaffolding protein Girdin localizes to the proximal regions of centrioles and regulates BB positioning and ciliogenesis in Caenorhabditis elegans sensory neurons and human RPE-1 cells. Girdin depletion alters localization of the intercentriolar linker and ciliary rootlet component rootletin, and rootletin knockdown in RPE-1 cells mimics Girdin-dependent phenotypes. C. elegans Girdin also regulates localization of the apical junction component AJM-1, suggesting that in nematodes Girdin may position BBs via rootletin- and AJM-1-dependent anchoring to the cytoskeleton and plasma membrane, respectively. Together, our results describe a conserved role for Girdin in BB positioning and ciliogenesis. •Girdin regulates cilia morphology in C. elegans sensory neurons and RPE-1 cells•Girdin localizes to the proximal regions of centrioles in ciliated cells•Basal body positioning is disrupted upon Girdin knockdown•Girdin is required to localize rootletin at basal bodies The mechanisms by which basal bodies are positioned to template ciliogenesis at the correct cellular location are largely unknown. Nechipurenko et al. show that the signaling and scaffolding protein Girdin regulates basal body positioning and ciliogenesis, in part via localization of rootletin in C. elegans sensory neurons and human cells.