Propagation of Dachsous-Fat Planar Cell Polarity

Abstract

SUMMARY The Fat pathway controls both planar cell polarity (PCP) and organ growth [1, 2]. Fat signaling is regulated by the graded expression of the Fat ligand Dachsous (Ds), and the cadherin-domain kinase Four-jointed (Fj). The vectors of these gradients influence PCP [1], whereas their slope can influence growth [3, 4]. The Fj and Ds gradients direct the polarized membrane localization of the myosin Dachs, which is a crucial downstream component of Fat signaling [5–7]. Here we show that re-polarization of Dachs by differential expression of Fj or Ds can propagate through the wing disc, which indicates that Fj and Ds gradients can be measured over long range. Through characterization of tagged genomic constructs, we show that Ds and Fat are themselves partially polarized along the endogenous Fj and Ds gradients, providing a mechanism for propagation of PCP within the Fat pathway. We also identify a biochemical mechanism that might contribute to this polarization by showing that Ds is subject to endoproteolytic cleavage, and that the relative levels of Ds isoforms are modulated by Fat.

A global pattern of mechanical stress polarizes cell divisions and cell shape in the growing Drosophila wing disc

“…It is planar polarized in the wing disc at the junction level, with one side of each cell-cell junction containing more Dachs, along a proximo-distal gradient (Fig. 3A, left-hand schematic) (Ambegaonkar et al, 2012;Mao et al, 2006;Schwank et al, 2011b). Dachs has also been proposed to be polarized in the wing disc at the cellular level, with tangent junctions being enriched compared with radial junctions, leading to a radial bias in cell shape (Fig.…”

“…There is significant evidence for the activity of Dachs to be polarized. It was shown that, at the singlejunction level, Dachs enriches one side more than the other along a distal-to-proximal gradient (Ambegaonkar et al, 2012;Mao et al, 2006;Schwank et al, 2011a). Our observations were not designed to resolve such a polarity (we could not resolve individual sides of a junction).…”

An intracellular partitioning-based framework for tissue cell polarity in plants and animals

“…Cells in the eye become polarised through preferential distribution of the cadherin Ds (A*) to one cell end and its binding partner the cadherin Ft (B*) to the opposite cell end (Ambegaonkar et al, 2012;Brittle et al, 2012). Planar polarity patterns are specified by opposite gradients in expression of Ds and the Golgi-associated protein Four-jointed (Fj) (Simon, 2004).…”

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

“…We confirmed by Western blot the expression of DsIntra protein. Similar levels of DsIntra were observed in wt and DsFL expressing cells, which rules out the possibility that DsIntra is a peptide deriving from proteolytic cleavage of DsFL, as has been suggested to explain the existence of small bands detected by a Ds antibody [26].…”