Targeting of [beta]-Arrestin2 to the Centrosome and Primary Cilium: Role in Cell Proliferation Control

• Published in: PloS one Vol. 3; no. 11; p. e3728
• Main Authors: Molla-Herman, Anahi, Boularan, Cedric, Ghossoub, Rania, Scott, Mark G. H, Burtey, Anne, Zarka, Marion, Saunier, Sophie, Concordet, Jean-Paul, Marullo, Stefano, Benmerah, Alexandre
• Format: Journal Article
• Language: English
• Published: Public Library of Science 14.11.2008
• Subjects: G proteins; Membrane proteins
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0003728

The primary cilium is a sensory organelle generated from the centrosome in quiescent cells and found at the surface of most cell types, from where it controls important physiological processes. Specific sets of membrane proteins involved in sensing the extracellular milieu are concentrated within cilia, including G protein coupled receptors (GPCRs). Most GPCRs are regulated by [beta]-arrestins, [beta]arr1 and [beta]arr2, which control both their signalling and endocytosis, suggesting that [beta]arrs may also function at primary cilium. In cycling cells, [beta]arr2 was observed at the centrosome, at the proximal region of the centrioles, in a microtubule independent manner. However, [beta]arr2 did not appear to be involved in classical centrosome-associated functions. In quiescent cells, both in vitro and in vivo, [beta]arr2 was found at the basal body and axoneme of primary cilia. Interestingly, [beta]arr2 was found to interact and colocalize with 14-3-3 proteins and Kif3A, two proteins known to be involved in ciliogenesis and intraciliary transport. In addition, as suggested for other centrosome or cilia-associated proteins, [beta]arrs appear to control cell cycle progression. Indeed, cells lacking [beta]arr2 were unable to properly respond to serum starvation and formed less primary cilia in these conditions. Our results show that [beta]arr2 is localized to the centrosome in cycling cells and to the primary cilium in quiescent cells, a feature shared with other proteins known to be involved in ciliogenesis or primary cilium function. Within cilia, [beta]arr2 may participate in the signaling of cilia-associated GPCRs and, therefore, in the sensory functions of this cell "antenna".