Biology subjects

Parsons, J.

Publications and source records attributed to Parsons, J..

3 recordsLinked to original sources

bioRxiv2021

Reciprocal Priming between RTKs within Recycling Endosomes Orchestrates Cellular Signaling Outputs

Integration of signalling downstream of individual receptor tyrosine kinases (RTKs) is crucial to fine tune cellular homeostasis during development and in pathological conditions, including breast cancer. However, how signalling integration is regulated and whether the endocytic fate of single receptors controls such signalling integration remains poorly elucidated. Combining quantitative phosphoproteomics and targeted assays, we generated a detailed picture of recycling-dependent fibroblast growth factor (FGF) signalling in breast cancer cells, with a focus on distinct FGF receptors (FGFRs). We discovered reciprocal priming between FGFRs and epidermal growth factor (EGF) receptor (EGFR) that is coordinated at recycling endosomes. FGFR recycling ligands induce EGFR phosphorylation on threonine 693. This phosphorylation event alters both FGFR and EGFR trafficking and primes FGFR-mediated proliferation but not cell invasion. In turn, FGFR signalling primes EGF-mediated outputs via EGFR threonine 693 phosphorylation. This reciprocal priming between distinct families of RTKs from recycling endosomes exemplifies a novel signalling integration hub where recycling endosomes orchestrate cellular behaviour. Therefore, targeting reciprocal priming over individual receptors may improve personalized therapies in breast and other cancers.

cell biology↗

bioRxiv2020

Stable Protein Sialylation in Physcomitrella

Recombinantly produced proteins are indispensable tools for medical applications. Since the majority of them are glycoproteins, their N-glycosylation profiles are major determinants for their activity, structural properties and safety. For therapeutical applications, a glycosylation pattern adapted to product and treatment requirements is advantageous. Physcomitrella (Physcomitrium patens, moss) is able to perform highly homogeneous complex-type N-glycosylation. Additionally, it has been glyco-engineered to eliminate plant-specific sugar residues by knock-out of the {beta}1,2-xylosyltransferase and 1,3-fucosyltransferase genes ({Delta}xt/ft). Furthermore, P. patens meets wide-ranging biopharmaceutical requirements such as GMP compliance, product safety, scalability and outstanding possibilities for precise genome engineering. However, all plants, in contrast to mammals, lack the capability to perform N-glycan sialylation. Since sialic acids are a common terminal modification on human N-glycans, the property to perform N-glycan sialylation is highly desired within the plant-based biopharmaceutical sector. In this study, we present the successful achievement of protein N-glycan sialylation in stably transformed P. patens. The sialylation ability was achieved in a {Delta}xt/ft moss line by stable expression of six mammalian coding sequences combined with targeted organelle-specific localization of the encoded enzymes responsible for synthesis, activation, transport and transfer of sialic acid. Production of free and (CMP)-activated sialic acid was proven. The glycosidic anchor for the attachment of terminal sialic acid was generated by the introduction of a chimeric human {beta}1,4-galactosyltransferase gene under the simultaneous knock-out of the gene encoding the endogenous {beta}1,3-galactosyltransferase. Functional complex-type N-glycan sialylation was confirmed via mass spectrometric analysis of a stably co-expressed recombinant human protein.

bioengineering↗

bioRxiv2020

Biodiversity and niche partitioning in an anaerobic benzene degrading culture

A key question in microbial ecology is what the driving forces behind the persistence of large biodiversity in natural environments are. We studied a microbial community with more than 100 different types of species which evolved in a 15-years old bioreactor with benzene as the main carbon and free energy source and nitrate as the electron acceptor. We demonstrate that only a few community members are able to degrade benzene, and that most of the others feed on the metabolic left-overs or on the contents of dead cells making up a food web with different trophic levels. As a result of niche partitioning, a high species richness is maintained and the complexity of a natural community is stabilized in a relatively simple environment. This view highlights the importance of species interactions and interdependencies, which drive microbial community structure and function. These mechanisms may well be conserved across ecosystems.

ecology↗