Identification of protein-protein interactions is a major goal of biological research. Despite technical advances over the last two decades, important but still largely unsolved challenges include the high-throughput detection of interactions directly from primary tissue and the identification of interactors of insoluble proteins that form higher-order structures. We have developed a novel, proximity-based labeling approach that uses antibodies to guide biotin deposition onto adjacent proteins in fixed cells and primary tissues. We showed our method to be specific and sensitive by labeling a mitochondrial matrix protein. Next, we used this method to profile the dynamic interactome of lamin A/C in multiple cell and tissue types under various treatment conditions. The ability to detect proximal proteins and putative interactors in intact tissues, and to quantify changes caused by different conditions or in the presence of disease mutations, can provide a new window into cell biology and disease pathogenesis.

Identification of protein-protein interactions is a major goal of biological research. Despite technical advances over the last two decades, important but still largely unsolved challenges include the high-throughput detection of interactions directly from primary tissue and the identification of interactors of insoluble proteins that form higher-order structures. We have developed a novel, proximity-based labeling approach that uses antibodies to guide biotin deposition onto adjacent proteins in fixed cells and primary tissues. We used this method to profile the dynamic interactome of lamin A/C in multiple cell and tissue types under various treatment conditions. Our results suggest a considerable variation in the composition of the nuclear envelope of different tissues. Of note, DNA damage response proteins Ku70 and Ku80 are more abundant in the vicinity of lamin A/C after thermal stress. This increased affinity also applies to the progerin isoform, potentially contributing to the premature aging phenotype of Hutchinson-Gilford progeria syndrome. The ability to detect protein-protein interactions in intact tissues, and to compare affinities quantitatively under different conditions or in the presence of disease mutations, can provide a new window into cell biology and disease pathogenesis.All rights reserved. No reuse allowed without permission.(which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.

In the version of this article initially published, the introduction focused on methods for characterizing the nuclear envelope and did not include a comprehensive overview of proximity-based methods, some of which have similarly utilized antibody-conjugated peroxidase for proximity labeling by biotin deposition (refs 1-4 below). The authors believe they should have included these references and apologize for the omission.