Wallingford, J. | bioRxiv Science

bioRxiv2017

A phase separated organelle at the root of motile ciliopathy

Hundreds of different cell types emerge in the developing embryo, each of which must compartmentalize cell type specific biochemical processes in a crowded intracellular environment. To study cell type specific compartmentalization, we examined motile ciliated cells, which must assemble vast numbers of dynein motors to drive ciliary beating, as mutation of dyneins or their assembly factors causes motile ciliopathy. We show that dyneins, their assembly factors, and chaperones all concentrate together in Dynein Assembly Particles (DynAPs). These phase-separated organelles are specific to ciliated cells but share machinery with stress granules. Our data suggest that a common framework underlies ubiquitous and cell-type specific phase separated organelles and that one such organelle is defective in a human genetic disease.

cell biology↗

bioRxiv2017

High-content protein localization screening in vivo reveals novel regulators of multiciliated cell development and function

Multiciliated cells (MCCs) drive fluid flow in diverse tubular organs and are essential for development and homeostasis of the vertebrate central nervous system, airway, and reproductive tracts. These cells are characterized by dozens or hundreds of long, motile cilia that beat in a coordinated and polarized manner (Brooks and Wallingford, 2014). In recent years, genomic studies have not only elucidated the transcriptional hierarchy for MCC specification, but also identified myriad new proteins that govern MCC ciliogenesis, cilia beating, or cilia polarization (e.g. (Choksi et al., 2014b; Chung et al., 2014; Hoh et al., 2012; Ma et al., 2014; Treutlein et al., 2014)). Interestingly, this burst of genomic data has also highlighted the obvious importance of the \"ignorome,\" that large fraction of vertebrate genes that remain only poorly characterized (Pandey et al., 2014). Understanding the function of novel proteins with little prior history of study presents a special challenge, especially when faced with large numbers of such proteins. Here, we explored the MCC ignorome by defining the subcellular localization of 260 poorly defined proteins in vertebrate MCCs in vivo. Moreover, functional analyses that arose from results of the screen provide novel insights into the mechanisms by which the actin cytoskeleton simultaneously influences diverse aspects of MCC biology, including basal body docking, and ciliogenesis.

cell biology↗