Androgen receptor (AR) function depends on interactions with a large set of nuclear partners, but how AR engages this interactome inside the nucleus over time has remained unclear. The authors set out to create a minute-scale temporal atlas of the nuclear androgen receptor proximal interactome to define which proteins are AR-proximal, when they are recruited, and how molecular handoffs occur during early AR-dependent events.
The work aims to convert the long catalog of AR coregulators into a temporally resolved, quantitative framework that reflects AR engagement at chromatin loci and associated molecular processes.
The study used proximity-labeling quantitative mass spectrometry (PL-qMS) to detect proteins proximal to nuclear AR in an acute androgen response. Experiments were performed in androgen-treated LNCaP prostate cancer cells. Sampling was performed across six discrete time points at minute-scale resolution to capture early temporal dynamics of AR-proximal interactions.
PL-qMS in this context identifies proteins that are spatially near AR in the nucleus during the androgen response, generating a quantitative readout of temporal recruitment and proximity.
Using PL-qMS across the six time points, the authors resolved 3,378 nuclear AR-proximal interacting proteins (AR-PIPs). This dataset captured 84.2% of the known AR-interactome cataloged prior to the study, indicating extensive coverage of previously reported AR partners.
The resulting atlas therefore represents a broad and quantitative map of nuclear proteins that come into proximity with AR during the androgen response in this prostate cancer cell model.
The minute-scale temporal sampling allowed the authors to observe the sequential recruitment of proteins to AR in the nucleus. The atlas recapitulates the established cyclic sequential recruitment model previously described at AR-regulated loci by classical chromatin immunoprecipitation (ChIP) approaches. By resolving AR-proximal proteins across time, the dataset distinguishes early, transient proximities from later or sustained associations, providing a more nuanced view of AR-dependent molecular events.
This temporal information converts static listings of AR coregulators into a time-ordered, quantitative portrait of AR engagement with nuclear processes.
Embedded within the canonical chromatin recruitment signature, the temporal atlas uncovered a notable early event: a time-resolved translation-to-transcription handoff. Specifically, cap-binding regulators eIF4G and 4E-BP1 were detected as transiently AR-proximal at the earliest time points sampled.
The proximity of eIF4G and 4E-BP1 to nuclear AR at early time points was independently verified by proximity ligation assay (PLA), supporting the PL-qMS observation of a transient cap-binding protein presence near AR during the initiation of the androgen response.
This finding suggests that components traditionally associated with cytoplasmic translation initiation may transiently associate with nuclear AR during early stages of AR-dependent transcriptional regulation, consistent with a handoff between translation-associated factors and transcriptional machinery.
The atlas recovered 100% of previously known AR interactors reported in the Launonen 2021 ChIP-SICAP chromatome, demonstrating strong concordance with an independent chromatin-focused dataset. In addition to reproducing established chromatin recruitment cycles observed by classical ChIP, the PL-qMS approach provided quantitative temporal detail at minute resolution not available from endpoint or lower-temporal-resolution methods.
Together, these comparisons indicate that the PL-qMS temporal atlas both complements and extends prior chromatin- and interactome-focused studies of AR.
By providing a minute-scale temporal map of nuclear AR proximity, the study reframes the AR coregulator catalog as a dynamic process rather than a static list. The identification of an early translation-to-transcription handoff and the temporal ordering of AR-proximal proteins offer a framework for understanding how chromatin recruitment, coregulator exchange, and potential cross-talk with translation-associated factors are coordinated during AR-driven gene regulation.
For research in prostate cancer biology and transcriptional regulation, the atlas offers a resource to prioritize candidate AR interactors for functional follow-up based on their temporal recruitment profiles.
This report is a preprint and has not been certified by peer review. Details beyond those presented in the preprint (for example, full experimental parameters, raw datasets, or extended validation outside the described PLA verification) are not reported here and should be consulted directly in the source manuscript and supplementary materials.
The authors state copyright terms and licensing for the preprint; readers should also note the preprint status when interpreting results.