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How proteins interact with one another and with other macromolecules, their organization in cells and how these associations are modulated following perturbations long have defined an important branch of the field of functional proteomics. In the past 10 years, approaches that enable the study of these connections in the context of live cells — and now live organisms — have revolutionized the role of proteomics in cell biology.

This session at the 2021 ASBMB Annual Meeting focuses on proximity-dependent labeling approaches, which allow for the covalent tagging of proteins that have come in close proximity to a bait protein (a protein of interest fused to an enzyme) in the context of living cells. Coupling of this strategy to mass spectrometric identification of the labeled proteins permits the characterization of cellular organization.

Since its first implementation to identify the components of the nuclear lamina in cultured cells, proximity-dependent biotinylation has contributed to better understanding of the composition of both membrane-bound and membraneless organelles, defined new signaling complex components, and illuminated the molecular mechanisms underlying several diseases. Proximity-dependent biotinylation methods, including APEX and BioID, still are developing, permitting new experimental modalities and answering increasingly complex questions.

The three presenters selected by the editorial leadership of Â鶹´«Ã½É«ÇéƬ & Cellular Proteomics are early-career researchers pushing the boundaries of proximity-dependent biotinylation methods and their applications.

Tess C. Branon, a postdoctoral fellow at the University of California, Berkeley, will present her work on the directed evolution of promiscuous biotin ligases for efficient proteomic mapping in vivo.

Geoffrey Hesketh, a postdoctoral fellow at the Lunenfeld–Tanenbaum Research Institute of Mount Sinai Hospital in Toronto, will describe how he used proximity-dependent sensors to reveal new intricacies in amino acid signaling.

Ilia Droujinine, a principal investigator and Scripps fellow at Scripps Research in California, will introduce new work exploring protein trafficking by in vivo tissue-specific labeling in Drosophila.

Tess C. Branon

Geoffrey Hesketh

Ilia Droujinine