Abstract
BRCA1-associated protein 1 (BAP1) is a tumor suppressor and its loss can result in mesothelioma, uveal and cutaneous melanoma, clear cell renal cell carcinoma and bladder cancer. BAP1 is a deubiquitinating enzyme of the UCH class that has been implicated in various cellular processes like cell growth, cell cycle progression, ferroptosis, DNA damage response and ER metabolic stress response. ASXL proteins activate BAP1 by forming the polycomb repressive deubiquitinase (PR-DUB) complex which acts on H2AK119ub1. Besides the ASXL proteins, BAP1 is known to interact with an established set of additional proteins. Here, we identify novel BAP1 interacting proteins in the cytoplasm by expressing GFP-tagged BAP1 in an endogenous BAP1 deficient cell line using affinity purification followed by mass spectrometry (AP-MS) analysis. Among these novel interacting proteins are Histone acetyltransferase 1 (HAT1) and all subunits of the heptameric coat protein complex I (COPI) that is involved in vesicle formation and protein cargo binding and sorting. We validate that the HAT1 and COPI interactions occur at endogenous levels but find that this interaction with COPI is not mediated through the C-terminal KxKxx cargo sorting signals of the COPI complex.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Line, Tumor
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Coat Protein Complex I / metabolism*
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Cytoplasm / metabolism*
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Gene Expression Regulation, Neoplastic
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Gene Knockout Techniques
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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HeLa Cells
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Histone Acetyltransferases / metabolism*
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Humans
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Mass Spectrometry
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Mutation
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Neoplasms / metabolism*
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Proteomics / methods*
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Recombinant Proteins / metabolism
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Tumor Suppressor Proteins / genetics*
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Tumor Suppressor Proteins / metabolism*
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Ubiquitin Thiolesterase / genetics*
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Ubiquitin Thiolesterase / metabolism*
Substances
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BAP1 protein, human
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Coat Protein Complex I
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Recombinant Proteins
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Tumor Suppressor Proteins
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Green Fluorescent Proteins
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Histone Acetyltransferases
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histone acetyltransferase type B complex
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Ubiquitin Thiolesterase
Grants and funding
KWF Kankerbestrijding (DCS):Titia K Sixma 2015-8082; TKS & HvA;
www.kwf.nl Oncode Institute; TKS;
www.oncode.nl NWO | Aard- en Levenswetenschappen, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO-ALW OPEN): 2015.091; TKS;
www.nwo.nl Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO): X-omics Initiative; NKI;
www.nwo.nl The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.