Identification of hepatic protein-protein interaction targets for betaine homocysteine S-methyltransferase

PLoS One. 2018 Jun 20;13(6):e0199472. doi: 10.1371/journal.pone.0199472. eCollection 2018.

Abstract

Protein-protein interactions are an important mechanism for the regulation of enzyme function allowing metabolite channeling, crosstalk between pathways or the introduction of post-translational modifications. Therefore, a number of high-throughput studies have been carried out to shed light on the protein networks established under different pathophysiological settings. Surprisingly, this type of information is quite limited for enzymes of intermediary metabolism such as betaine homocysteine S-methyltransferase, despite its high hepatic abundancy and its role in homocysteine metabolism. Here, we have taken advantage of two approaches, affinity purification combined with mass spectrometry and yeast two-hybrid, to further uncover the array of interactions of betaine homocysteine S-methyltransferase in normal liver of Rattus norvegicus. A total of 131 non-redundant putative interaction targets were identified, out of which 20 were selected for further validation by coimmunoprecipitation. Interaction targets validated by two different methods include: S-methylmethionine homocysteine methyltransferase or betaine homocysteine methyltransferase 2, methionine adenosyltransferases α1 and α2, cAMP-dependent protein kinase catalytic subunit alpha, 4-hydroxyphenylpyruvic acid dioxygenase and aldolase b. Network analysis identified 122 nodes and 165 edges, as well as a limited number of KEGG pathways that comprise: the biosynthesis of amino acids, cysteine and methionine metabolism, the spliceosome and metabolic pathways. These results further expand the connections within the hepatic methionine cycle and suggest putative cross-talks with additional metabolic pathways that deserve additional research.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Betaine-Homocysteine S-Methyltransferase / chemistry
  • Betaine-Homocysteine S-Methyltransferase / metabolism*
  • Gene Ontology
  • HMGB1 Protein / metabolism
  • Liver / metabolism*
  • Male
  • Mice
  • Open Reading Frames / genetics
  • Protein Binding
  • Protein Interaction Mapping*
  • Protein Interaction Maps
  • Rats, Wistar
  • Reproducibility of Results

Substances

  • HMGB1 Protein
  • Betaine-Homocysteine S-Methyltransferase

Grants and funding

This work was supported by grants of the Ministerio de Economía, Industria y Competitividad (BFU2005-00050, BFU2008-00666, BFU2009-08977 to MAP; BFU2008-04285 to FP). The CNIC is supported by the Ministerio de Economía, Industria y Competitividad (MEIC) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.