2. Academic Validation
  3. Human Regulatory Protein Ki-1/57 Is a Target of SUMOylation and Affects PML Nuclear Body Formation

Human Regulatory Protein Ki-1/57 Is a Target of SUMOylation and Affects PML Nuclear Body Formation

  • J Proteome Res. 2017 Sep 1;16(9):3147-3157. doi: 10.1021/acs.jproteome.7b00001.
Ângela Saito 1,  Edmarcia E Souza 2,  Fernanda C Costa 3,  Gabriela V Meirelles 1,  Kaliandra A Gonçalves 1,  Marcos T Santos 4,  Gustavo C Bressan 5,  Mark E McComb 6,  Catherine E Costello 6,  Stephen A Whelan 6,  Jörg Kobarg 2 7
Affiliations

Affiliations

  • 1 Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil.
  • 2 Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas , Campinas, São Paulo 13083-859, Brazil.
  • 3 Instituto de Física de São Carlos, Universidade de São Paulo , São Carlos, São Paulo 13563-120, Brazil.
  • 4 ONKOS Molecular Diagnostics, Inc. , R&D Department, Ribeirão Preto, São Paulo 14056-680, Brazil.
  • 5 Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa (UFV) , Viçosa, Minas Gerais 36570-000, Brazil.
  • 6 Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States.
  • 7 Departamento de Bioquímica e Biologia Tecidual, Programa de Pós-graduação em Biologia Funcional e Molecular, Universidade Estadual de Campinas , Campinas, São Paulo 13083-862, Brazil.
PMID: 28695742 DOI: 10.1021/acs.jproteome.7b00001
Abstract

Ki-1/57 is a nuclear and cytoplasmic regulatory protein first identified in malignant cells from Hodgkin's lymphoma. It is involved in gene expression regulation on both transcriptional and mRNA metabolism levels. Ki-1/57 belongs to the family of intrinsically unstructured proteins and undergoes phosphorylation by PKC and methylation by PRMT1. Previous characterization of its protein interaction profile by yeast two-hybrid screening showed that Ki-1/57 interacts with proteins of the SUMOylation machinery, the SUMO E2 conjugating Enzyme UBC9 and the SUMO E3 ligase PIAS3, which suggested that Ki-1/57 could be involved with this process. Here we identified seven potential SUMO target sites (lysine residues) on Ki-1/57 sequence and observed that Ki-1/57 is modified by SUMO proteins in vitro and in vivo. We showed that SUMOylation of Ki-1/57 occurred on lysines 213, 276, and 336. In transfected cells expressing FLAG-Ki-1/57 wild-type, its paralog FLAG-CGI-55 wild-type, or their non-SUMOylated triple mutants, the number of PML-nuclear bodies (PML-NBs) is reduced compared with the control cells not expressing the constructs. More interestingly, after treating cells with arsenic trioxide (As2O3), the number of PML-NBs is no longer reduced when the non-SUMOylated triple mutant Ki-1/57 is expressed, suggesting that the SUMOylation of Ki-1/57 has a role in the control of As2O3-induced PML-NB formation. A proteome-wide analysis of Ki-1/57 partners in the presence of either SUMO-1 or SUMO-2 suggests that the involvement of Ki-1/57 with the regulation of gene expression is independent of the presence of either SUMO-1 or SUMO-2; however, the presence of SUMO-1 strongly influences the interaction of Ki-1/57 with proteins associated with cellular metabolism, maintenance, and cell cycle.

Keywords

CGI-55; Ki-1/57; PML-NBs; SUMOylation; arsenic trioxide; posttranslational modifications.

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