Biology subjects

Backer, W.

Publications and source records attributed to Backer, W..

3 recordsLinked to original sources

bioRxiv2022

Src42A is required for E-cadherin dynamics at cell junctions during Drosophila axis elongation

Src kinases are important regulators of cell adhesion. Here we explored the function of Src42A in junction remodelling during Drosophila gastrulation. Src42A is required for tyrosine phosphorylation at bicellular and tricellular junctions in germband cells and localizes to hotspots of mechanical tension. The role of Src42A was investigated using maternal RNAi and by CRISPR-Cas9-induced germline mosaics. We find that during cell intercalations, Src42A is required for the contraction of junctions at anterior-posterior cell interfaces. The planar polarity of E-cadherin is compromised and E-cadherin accumulates at tricellular junctions after Src42A knock down. Furthermore, we provide evidence that Src42A acts in parallel to Abl, which has also been implicated in cell intercalations. Our data suggest that Src42A is involved in two related processes, one affecting tension generated by the planar polarity of MyoII and secondly, it can act as a signalling factor at tAJs in controlling E-cadherin residence time.

developmental biology↗

bioRxiv2022

Acute manipulation and real-time visualization of membrane trafficking and exocytosis in Drosophila

Intracellular trafficking of secretory proteins plays key roles in animal development and physiology, but tools for investigating dynamics of membrane trafficking have been limited to cultured cells. Here we present a system that enables acute manipulation and real-time visualization of membrane trafficking through reversible retention of proteins in the endoplasmic reticulum (ER) in living multicellular organisms. By adapting the "retention using selective hooks" (RUSH) approach to Drosophila, we show that trafficking of GPI-linked, secreted, and transmembrane proteins can be controlled with high temporal precision in intact animals and cultured organs. We demonstrate the potential of this approach by analyzing the kinetics of ER exit and apical secretion and the spatiotemporal dynamics of tricellular junction assembly in epithelia of living embryos. Furthermore, we show that controllable ER-retention enables tissue-specific depletion of secretory protein function. The system is broadly applicable to visualize and manipulate membrane trafficking in diverse cell types in vivo.

cell biology↗

bioRxiv2019

Matrix metalloproteinase 1 modulates invasive behavior of tracheal branches during ingression into Drosophila flight muscles

Tubular networks like the vasculature extend branches throughout the bodies of animals, but how developing vessels interact with and invade tissues is not well understood. We investigated the underlying mechanisms using the developing tracheal tube network of Drosophila indirect flight muscles (IFMs) as a model. Live imaging revealed that tracheal sprouts invade IFMs directionally with growth-cone-like structures at branch tips. Ramification inside IFMs proceeds until tracheal branches fill the myotube. However, individual tracheal cells occupy largely separate territories, possibly mediated by cell-cell repulsion. Matrix metalloproteinase 1 (MMP1) is required in tracheal cells for normal invasion speed and for the dynamic organization of growth-cone-like branch tips. MMP1 remodels the Collagen IV-containing matrix around branch tips and promotes degradation of Branchless FGF in cultured cells. Thus, tracheal-derived MMP1 may play dual roles in sustaining branch invasion by modulating ECM properties as well as by shaping the distribution of the FGF chemoattractant.

cell biology↗