Beati, H. | bioRxiv Science

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↗

bioRxiv2019

SILAC-based quantitative proteomic analysis of Drosophila gastrula stage embryos mutant for fibroblast growth factor signaling

The application of quantitative proteomics in model organisms has been successful in determining changes in the proteome under distinct physiological conditions. Quantitative mass spectrometry-based proteomic analyses in combination with genetics provide powerful tools in developmental cell signaling research. Drosophila melanogaster is one of the most widely used genetic models for studying development and disease. Here we combined quantitative proteomics with genetic selection to determine global changes in the proteome upon depletion of the Heartless (Htl) Fibroblast-Growth Factor (FGF) receptor signaling in Drosophila embryos at early gastrulation stages. We present a robust, single generation SILAC (stable isotope labeling with amino acids in cell culture) protocol for labeling proteins in early embryos and for selection of homozygously mutant embryos at pre-gastrula stages using an independent genetic marker. Our analyses detected quantitative changes in the global proteome of htl mutant embryos during gastrulation. We identified distinct classes of down-regulated and up-regulated proteins and network analyses indicates functionally related groups of proteins in each class. These data suggest that FGF signaling in the early embryo affects global changes in the abundance of metabolic, nucleoplasmic, cytoskeletal and endomembrane transport proteins.

developmental biology↗