Defects in the structure or function of the primary cilium, an antennae-like structure whose functional integrity has been linked to the suppression of uncontrolled kidney epithelial cell proliferation, are a common feature of genetic disorders characterized by kidney cysts. However, the mechanisms by which primary cilia are maintained remain poorly defined. von Hippel-Lindau (VHL) disease is characterized by the development of premalignant renal cysts and arises because of functional inactivation of the VHL tumour suppressor gene product, pVHL. Here, we show that pVHL and glycogen synthase kinase (GSK)3beta are key components of an interlinked signalling pathway that maintains the primary cilium. Although inactivation of either pVHL or GSK3beta alone did not affect cilia maintenance, their combined inactivation leads to loss of cilia. In VHL patients, GSK3beta is subjected to inhibitory phosphorylation in renal cysts, but not in early VHL mutant lesions, and these cysts exhibit reduced frequencies of primary cilia. We propose that pVHL and GSK3beta function together in a ciliary-maintenance signalling network, disruption of which enhances the vulnerability of cells to lose their cilia, thereby promoting cyst formation.

Significance Spatiotemporal coordination of cell growth underlies tissue development and disease. Mechanical feedback between cells has been proposed as a regulatory mechanism for growth control both in vivo and in cultured cells undergoing contact inhibition of proliferation. Evidence beyond theoretical and correlative observations falls short. In this study, we probe the impact of mechanical tissue perturbations on cell cycle progression by monitoring cell cycle dynamics of cells in tissues subject to acute changes in boundary conditions, as well as tissue stretching and compression. Taken together, we conclude that the ability of tissues to support cell cycle progression adapts to the available space through a memory-free control mechanism, which may coordinate proliferation patterns to maintain tissue homeostasis.

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The product of the von Hippel-Lindau tumor suppressor gene stabilizes microtubules by inhibiting GTPase activity.