PT  - JOURNAL ARTICLE
AU  - Miguel Bernabé-Rubio
AU  - Minerva Bosch-Fortea
AU  - Esther García
AU  - Jorge Bernardino de la Serna
AU  - Miguel A. Alonso
TI  - The ciliary membrane of polarized epithelial cells stems from a midbody remnant-associated membrane patch with condensed nanodomains
AID  - 10.1101/667642
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 667642
4099  - http://biorxiv.org/content/early/2019/06/11/667642.short
4100  - http://biorxiv.org/content/early/2019/06/11/667642.full
AB  - The primary cilium is a specialized plasma membrane protrusion that harbors receptors involved in important signaling pathways. Despite its central role in regulating cellular behavior, the biogenesis of the primary cilium is not fully understood. In fact, the source of the ciliary membrane remains a mystery in cell types that assemble their primary cilium entirely at the cell surface, such as polarized renal epithelial cells. After cytokinesis, the remnant of the midbody of these cells moves to the center of the apical surface, where it licenses the centrosome for ciliogenesis through an unidentified mechanism. Here, to investigate the origin of the ciliary membrane and the role of the midbody remnant, we analyzed membrane compaction and lipid dynamics at the microscale and nanoscale in living renal epithelial MDCK cells. We found that a specialized patch made of condensed membranes with restricted lipid lateral mobility surrounds the midbody remnant. This patch accompanies the remnant on its journey towards the centrosome and, once the two structures have met, the remnant delivers part of membranes of the patch to build the ciliary membrane. In this way, we have determined the origin of the ciliary membrane and the contribution of the midbody remnant to primary cilium formation in cells whose primary cilium is assembled at the plasma membrane.CAMPcentrosome-associated membrane patchFRAPfluorescence recovery after photobleachingGPgeneralized polarizationIMCD3inner medullary collecting duct 3MBRmidbody remnantMDCKMadin-Darby canine kidney cellsMKLP1mitotic kinesin-like protein 1RAMPremnant-associated membrane patchRICSraster image correlation spectroscopySTEDstimulated emission depletion