PT  - JOURNAL ARTICLE
AU  - Maria Brooun
AU  - Alexander Klimovich
AU  - Mikhail Bashkurov
AU  - Bret J. Pearson
AU  - Robert E. Steele
AU  - Helen McNeill
TI  - Ancestral role of Fat-like cadherins in planar cell polarity
AID  - 10.1101/602029
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 602029
4099  - http://biorxiv.org/content/early/2019/04/09/602029.short
4100  - http://biorxiv.org/content/early/2019/04/09/602029.full
AB  - Fat family cadherins are enormous proteins that regulate planar cell polarity (PCP) and cell adhesion in bilaterian animals. Their evolutionary origin can be traced back to prebilaterian species, but their ancestral function(s) are unknown. We identified Fat-like and Dachsous cadherins in Hydra, a member of the early-diverging metazoan phylum Cnidaria. Hydra has a simple body plan with only two epithelial layers and radial symmetry. We find that Hydra homologues of Fat-like (HyFat) and Dachsous (HyDs) co-localize at the apico-lateral membrane of ectodermal epithelial cells. Remarkably, HyFat is planar polarized perpendicular to the oral-aboral axis of the animal. Using knockdown approaches we found that HyFat is involved in the regulation of local cell alignment, but is dispensable for the global alignment of ectodermal myonemes along the oral-aboral axis. The intracellular domain (ICD) of HyFat is involved in the morphogenesis of ectodermal myonemes. Thus, Fat family cadherins have ancient, prebilaterian functions in cell adhesion, tissue organization and planar polarity.