PCGF2 negatively regulates arsenic trioxide-induced PML-RARA protein degradation via UBE2I inhibition in NB4 cells.
Arsenic trioxide (ATO) is a therapeutic agent for acute promyelocytic leukemia (APL) which induces PML-RARA protein degradation via enhanced UBE2I-mediated sumoylation. PCGF2, a Polycomb group protein, has been suggested as an anti-SUMO E3 protein by inhibiting the sumoylation of UBE2I substrates, HSF2 and RANGAP1, via direct interaction. Thus, we hypothesized ... that PCGF2 might play a role in ATO-induced PML-RARA degradation by interacting with UBE2I. PCGF2 protein was down-regulated upon ATO treatment in human APL cell line, NB4. Knockdown of PCGF2 in NB4 cells, in the absence of ATO treatment, was sufficient to induce sumoylation-, ubiquitylation- and PML nuclear body-mediated degradation of PML-RARA protein. Moreover, overexpression of PCGF2 protected ATO-mediated degradation of ectopic and endogenous PML-RARA in 293T and NB4 cells, respectively. In 293T cells, UBE2I-mediated PML-RARA degradation was reduced upon PCGF2 co-expression. In addition, UBE2I-mediated sumoylation of PML-RARA was reduced upon PCGF2 co-expression and PCGF2-UBE2I interaction was confirmed by co-immunoprecipitation. Likewise, endogenous PCGF2-UBE2I interaction was detected by co-immunoprecipitation and immunofluorescence assays in NB4 cells. Intriguingly, upon ATO-treatment, such interaction was disrupted and UBE2I was co-immunoprecipitated or co-localized with its SUMO substrate, PML-RARA. Taken together, our results suggested a novel role of PCGF2 in ATO-mediated degradation of PML-RARA that PCGF2 might act as a negative regulator of UBE2I via direct interaction.
Mesh Terms:
Antineoplastic Agents, Arsenicals, Cell Line, Tumor, Fluorescent Antibody Technique, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, HEK293 Cells, Humans, Immunoprecipitation, Leukemia, Promyelocytic, Acute, Oncogene Proteins, Fusion, Oxides, Polycomb Repressive Complex 1, Protein Binding, Proteolysis, RNA Interference, Signal Transduction, Sumoylation, Time Factors, Transfection, Ubiquitin-Conjugating Enzymes, Ubiquitination
Antineoplastic Agents, Arsenicals, Cell Line, Tumor, Fluorescent Antibody Technique, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, HEK293 Cells, Humans, Immunoprecipitation, Leukemia, Promyelocytic, Acute, Oncogene Proteins, Fusion, Oxides, Polycomb Repressive Complex 1, Protein Binding, Proteolysis, RNA Interference, Signal Transduction, Sumoylation, Time Factors, Transfection, Ubiquitin-Conjugating Enzymes, Ubiquitination
Biochim. Biophys. Acta
Date: Jul. 01, 2016
PubMed ID: 27030546
View in: Pubmed Google Scholar
Download Curated Data For This Publication
199189
Switch View:
- Interactions 3