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Pronobis, M.

Publications and source records attributed to Pronobis, M..

2 recordsLinked to original sources

In vivo proximity labeling identifies cardiomyocyte protein networks during zebrafish heart regeneration

Strategies have not been available until recently to uncover interacting protein networks specific to key cell types, their subcellular compartments, and their major regulators during complex in vivo events. Here we apply BioID2 proximity labeling to capture protein networks acting within cardiomyocytes during a key model of innate heart regeneration in zebrafish. Transgenic zebrafish expressing a promiscuous BirA2 localized to the entire myocardial cell or membrane compartment were generated, each identifying unique proteomes in adult cardiomyocytes that became altered during regeneration. BioID2 profiling for interactors with ErbB2, a co-receptor for the cardiomyocyte mitogen Nrg1, implicated Rho A as a target of ErbB2 signaling in cardiomyocytes. Blockade of Rho A during heart regeneration, or during cardiogenic stimulation by the mitogenic influences Nrg1, Vegfaa or Vitamin D, disrupted muscle creation. Our findings reveal proximity labeling as a useful resource to interrogate cell proteomes and signaling networks during tissue regeneration in zebrafish.

developmental biology↗

Wnt Regulation: Exploring Axin-Disheveled interactions and defining mechanisms by which the SCF E3 ubiquitin ligase is recruited to the destruction complex

Wnt signaling plays key roles in embryonic development and adult stem cell homeostasis, and is altered in human cancer. Signaling is turned on and off by regulating stability of the effector {beta}-catenin. The multiprotein destruction complex binds and phosphorylates {beta}-catenin, and transfers it to the SCF-TrCP E3-ubiquitin ligase, for ubiquitination and destruction. Wnt signals act though Dishevelled to turn down the destruction complex, stabilizing {beta}-catenin. Recent work clarified underlying mechanisms, but important questions remain. We explore {beta}-catenin transfer from the destruction complex to the E3 ligase, and test models suggesting Dishevelled and APC2 compete for association with Axin. We find that Slimb/TrCP is a dynamic component of the destruction complex biomolecular condensate, while other E3 proteins are not. Recruitment requires Axin and not APC, and Axins RGS domain plays an important role. We find that elevating Dishevelled levels in Drosophila embryos has paradoxical effects, promoting the ability of limiting levels of Axin to turn off Wnt signaling. When we elevate Dishevelled levels, it forms its own cytoplasmic puncta, but these do not recruit Axin. SIM imaging in mammalian cells suggests that this may result by promoting Dishevelled: Dishevelled interactions at the expense of Dishevelled:Axin interactions when Dishevelled levels are high.

cell biology↗