%0 Journal Article
%T Primary cilia utilize glycoprotein-dependent adhesion mechanisms to stabilize long-lasting cilia-cilia contacts
%A Carolyn Ott
%A Natalie Elia
%A Suh Jeong
%A Christine Insinna
%A Prabuddha Sengupta
%A Jennifer Lippincott-Schwartz
%J Cilia
%D 2012
%I BioMed Central
%R 10.1186/2046-2530-1-3
%X We identified cilia in rod photoreceptors and cholangiocytes in fixed mouse tissues and examined the structures that these cilia contact in vivo. We then utilized an MDCK cell culture model to characterize the nature of the contacts we observed.In retina and liver tissue, we observed that cilia from nearby cells touch one another. Using MDCK cells, we found compelling evidence that these contacts are stable adhesions that form bridges between two cells, or networks between many cells. We examined the nature and duration of the cilia-cilia contacts and discovered primary cilia movements that facilitate cilia-cilia encounters. Stable adhesions form as the area of contact expands from a single point to a stretch of tightly bound, adjacent cilia membranes. The cilia-cilia contacts persisted for hours and were resistant to several harsh treatments such as proteases and DTT. Unlike many other cell adhesion mechanisms, calcium was not required for the formation or maintenance of cilia adhesion. However, swainsonine, which blocks maturation of N-linked glycoproteins, reduced contact formation. We propose that cellular control of adhesion maintenance is active because cilia adhesion did not prevent cell division; rather, contacts dissolved during mitosis as cilia were resorbed.The demonstration that mammalian primary cilia formed prolonged, direct, physical contacts supports a novel paradigm: that mammalian primary cilia detect features of the extracellular space, not just as passive antennae, but also through direct physical contact. We present a model for the cycle of glycoprotein-dependent contact formation, maintenance, and termination, and discuss the implications for potential physiological functions of cilia-cilia contacts.Cilia extending away from a cell are ideally positioned to passively sample the extracellular environment. Primary cilia, motile cilia, and flagella are structurally and functionally similar microtubule-based organelles. Critical signaling compounds
%K Primary cilia
%K Contact
%K Adhesion
%K Direct sensing
%K Glycoprotein
%U http://www.ciliajournal.com/content/1/1/3