Identification of BRCA1-associated protein 1 (BAP1)-associated proteins

BRCA1-associated protein 1 (BAP1) is a multidomain deubiquitinase (DUB) with a ubiquitin carboxyl-terminal hydrolase (UCH) domain at its N-terminus. BAP1 mainly localizes in the nucleus and primarily functions as a transcriptional regulator in diverse cellular pathways, including cell proliferation, cell cycle progression, cell death and DNA repair. However, a comprehensive understanding of the mechanism by which the nucleocytoplasmic trafficking of BAP1 is regulated remains lacking. To identify protein factors that may be responsible for the nuclear import of BAP1, we used transiently expressed a N-terminally FLAG-tagged BAP1 in HEK293 freestyle (HEK293F) cells as a bait to pull down BAP1-interacting proteins for mass spectrometry-based proteomic analysis.