# Planar polarization of endogenous ADIP during Xenopus neurulation

## TL;DR

The protein ADIP shows planar polarization in Xenopus embryos, responding to mechanical cues during tissue formation.

## Contribution

This study reveals endogenous ADIP's role in planar cell polarity and its regulation by cytoskeletal networks during embryonic development.

## Key findings

- Endogenous ADIP polarizes during epithelial wound repair and in the anterior neural plate.
- ADIP polarization depends on microtubules, F-actin, and nonmuscle myosin II.
- ADIP polarization is reduced when the PCP component Diversin/Ankrd6 is depleted.

## Abstract

Coordinated cell polarity and force-responsive protein localization are essential for tissue morphogenesis, yet how embryonic cells sense forces and respond to mechanical cues remains a challenging question. Afadin- and α-actinin-binding protein (ADIP) has been implicated in microtubule minus-end anchoring, centrosome maturation and ciliogenesis. ADIP is also proposed to associate with the actomyosin cortex and regulate collective cell migration. ADIP behaves as a mechanosensitive planar cell polarity (PCP) protein when overexpressed in Xenopus embryos, but the distribution and regulation of endogenous ADIP has been unknown. Here we show that ADIP is present in early ectoderm as randomly distributed puncta that rapidly reorganize and polarize during epithelial wound repair. Endogenous ADIP also becomes enriched and planar polarized in the anterior neural plate towards the midline, consistent with its regulation by mechanical forces that operate during neural tube closure. ADIP polarization is attenuated by depletion of the core PCP component Diversin/Ankrd6, in agreement with the proposed interaction between the two proteins during PCP establishment. Finally, pharmacological disruption of microtubules, F-actin, and nonmuscle myosin II eliminates ADIP polarization in the neuroectoderm, indicating roles for microtubules and actomyosin networks in PCP. Together, these findings suggest that endogenous ADIP senses mechanical cues via the cytoskeletal machinery and functions in a context-dependent manner to control collective cell behaviors during vertebrate morphogenesis.

Summary: Mechanosensitive protein ADIP/SSX2IP is organized in endogenous complexes exhibiting planar polarity in Xenopus neural and nonneural ectoderm. ADIP localization requires microtubules and the actomyosin network.