Principles of planar polarity in animal development

Abstract

SummaryPlanar polarity describes the coordinated polarisation of cells or structures in the plane of a tissue. The patterning mechanisms that underlie planar polarity are well characterised in Drosophila, where many events are regulated by two pathways: the 'core' planar polarity complex and the Fat/Dachsous system. Components of both pathways also function in vertebrates and are implicated in diverse morphogenetic processes, some of which self-evidently involve planar polarisation and some of which do not. Here, we review the molecular mechanisms and cellular consequences of planar polarisation in diverse contexts, seeking to identify the common principles across the animal kingdom.

Involvement of the Wnt/β-catenin pathway in neurectoderm architecture in Platynereis dumerilii

“…We therefore isolated and characterized the expression patterns of several genes encoding members of the PCP pathway in Platynereis. The global module of the PCP pathway includes the atypical cadherins Fat and Dachsous (Ds), and their regulator Four-jointed (Fj), a Golgiassociated kinase 45,46 . This module establishes a polarity at the scale of the tissue via the opposite transcriptional gradients of ds and fj 45,46 .…”

“…These data suggest that the ventral neurectoderm of Platynereis is polarized via the Fat-Ds-Fj system along the mediolateral axis. The core PCP module, which relays the global polarity of the tissue at the cellular level, includes flamingo/ starrynight/celsr and Vangogh/strabismsus, which encode transmembrane proteins, as well as Prickle and diego/inversin, which encode cytoplasmic proteins 45,47 . Most of these genes are required for neurulation in the developing vertebrate CNS 8,10,48 .…”

Transcriptional analysis of the dachsous gene uncovers novel isoforms expressed during development in Drosophila

“…The Drosophila cadherinrelated Dachsous (Ds) and Fat (Ft) proteins and their homologues in vertebrates participate in the control of PCP and growth (reviewed in [1]). The current model is based on the heterophilic interaction between these two single-pass transmembrane proteins.…”

The intracellular carboxyl terminal domain of Vangl proteins contains plasma membrane targeting signals

“…4 Core PCP genes and proteins include Vangl/ Stbm (van gogh-like, strabismus), Pk (prickle), Dgo (diego), Fz (frizzled), Dsh (dishevelled), and Fmi (flamingo). 5 These assemble into membrane-bound multiprotein complexes that partition to the proximal (Vangl/Pk/Dgo) and distal side (Dsh/Fmi/Fz) of cells during PCP. The asymmetrical distribution of these complexes in adjacent cells propagates polarity signals to organize cells during PCP.…”

“…The asymmetrical distribution of these complexes in adjacent cells propagates polarity signals to organize cells during PCP. 5 The mechanisms underlying recruitment, assembly, and signaling by these membrane complexes remain unknown.…”