AR-V7 Utilizes a Noncanonical Nuclear Localization Signal to Sustain Androgen-Independent Nuclear Import and Signaling
- 1Department of Medicine, Division of Hematology Oncology, and Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
Abstract
AR-V7 is the most prevalent androgen receptor splice variant in metastatic castration-resistant prostate cancer, yet how it enters the nucleus independently of androgen binding has remained unclear. We previously demonstrated that AR-V7 undergoes nuclear import via a non-canonical pathway distinct from the microtubule-based, importin-/{beta}- and Ran-dependent mechanism used by full-length AR. Here, using systematic truncation and alanine-scanning mutagenesis, we identify a non-classical nuclear localization motif at the junction of the DNA-binding domain (DBD) and cryptic exon 3 (CE3) that is required for efficient AR-V7 nuclear import. Specific basic residues within the DBD and CE3 are required not only for nuclear entry but also for transcriptional activity. Unexpectedly, mutants retaining partial nuclear localization were transcriptionally silent, suggesting that CE3 contributes to transcriptional engagement through mechanisms separate from nuclear transport. Genome-wide transcriptomic analysis of a strongly import-deficient mutant confirmed that disruption of nuclear entry abolishes the AR-V7 transcriptional program. To map compartment-specific protein interactions, we applied antibody-guided photocatalytic proximity labeling. Nuclear AR-V7 associated most prominently with both canonical BAF and PBAF SWI/SNF chromatin remodeling complexes, together with known transcriptional coregulators and DNA-repair factors, whereas the cytoplasm-restricted mutant engaged different networks centered on mRNA deadenylation and decay, cytoskeletal regulation, and chaperone systems. Together, these findings define a variant-specific NLS, separate nuclear import from CE3-dependent transcriptional competence, and identify the cytoplasmic networks that become accessible when AR-V7 nuclear entry is impaired. They reveal two mechanistically distinct vulnerabilities for suppressing AR-V7 signaling: blocking nuclear translocation and disrupting CE3-dependent transcriptional engagement within the nucleus.
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BibTeX
@misc{castillo2026arv7,
title = {{AR-V7 Utilizes a Noncanonical Nuclear Localization Signal to Sustain Androgen-Independent Nuclear Import and Signaling}},
author = {U. del Castillo and N. E. Abou-Ghali and C. Burdette and M. Naidoo and C. C. Au and K. Kumari Sahu and X. Chen and X. Kathy Zhou and J. Geri and P. Giannakakou},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.23.753944},
url = {https://www.biorxiv.org/content/10.64898/2026.09.23.753944v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - AR-V7 Utilizes a Noncanonical Nuclear Localization Signal to Sustain Androgen-Independent Nuclear Import and Signaling
AU - U. del Castillo
AU - N. E. Abou-Ghali
AU - C. Burdette
AU - M. Naidoo
AU - C. C. Au
AU - K. Kumari Sahu
AU - X. Chen
AU - X. Kathy Zhou
AU - J. Geri
AU - P. Giannakakou
PY - 2026
DA - 2026/09/23
PB - bioRxiv
DO - 10.64898/2026.09.23.753944
UR - https://www.biorxiv.org/content/10.64898/2026.09.23.753944v1
AB - AR-V7 is the most prevalent androgen receptor splice variant in metastatic castration-resistant prostate cancer, yet how it enters the nucleus independently of androgen binding has remained unclear. We previously demonstrated that AR-V7 undergoes nuclear import via a non-canonical pathway distinct from the microtubule-based, importin-/{beta}- and Ran-dependent mechanism used by full-length AR. Here, using systematic truncation and alanine-scanning mutagenesis, we identify a non-classical nuclear localization motif at the junction of the DNA-binding domain (DBD) and cryptic exon 3 (CE3) that is required for efficient AR-V7 nuclear import. Specific basic residues within the DBD and CE3 are required not only for nuclear entry but also for transcriptional activity. Unexpectedly, mutants retaining partial nuclear localization were transcriptionally silent, suggesting that CE3 contributes to transcriptional engagement through mechanisms separate from nuclear transport. Genome-wide transcriptomic analysis of a strongly import-deficient mutant confirmed that disruption of nuclear entry abolishes the AR-V7 transcriptional program. To map compartment-specific protein interactions, we applied antibody-guided photocatalytic proximity labeling. Nuclear AR-V7 associated most prominently with both canonical BAF and PBAF SWI/SNF chromatin remodeling complexes, together with known transcriptional coregulators and DNA-repair factors, whereas the cytoplasm-restricted mutant engaged different networks centered on mRNA deadenylation and decay, cytoskeletal regulation, and chaperone systems. Together, these findings define a variant-specific NLS, separate nuclear import from CE3-dependent transcriptional competence, and identify the cytoplasmic networks that become accessible when AR-V7 nuclear entry is impaired. They reveal two mechanistically distinct vulnerabilities for suppressing AR-V7 signaling: blocking nuclear translocation and disrupting CE3-dependent transcriptional engagement within the nucleus.
ER -