Unmasking crucial residues in adipose triglyceride lipase for coactivation with comparative gene identification-58.

Journal: Journal of lipid research
PMID: 38135254

Abstract

Lipolysis is an essential metabolic process that releases unesterified fatty acids from neutral lipid stores to maintain energy homeostasis in living organisms. Adipose triglyceride lipase (ATGL) plays a key role in intracellular lipolysis and can be coactivated upon interaction with the protein comparative gene identification-58 (CGI-58). The underlying molecular mechanism of ATGL stimulation by CGI-58 is incompletely understood. Based on analysis of evolutionary conservation, we used site directed mutagenesis to study a C-terminally truncated variant and full-length mouse ATGL providing insights in the protein coactivation on a per-residue level. We identified the region from residues N209-N215 in ATGL as essential for coactivation by CGI-58. ATGL variants with amino acids exchanges in this region were still able to hydrolyze triacylglycerol at the basal level and to interact with CGI-58, yet could not be activated by CGI-58. Our studies also demonstrate that full-length mouse ATGL showed higher tolerance to specific single amino acid exchanges in the N209-N215 region upon CGI-58 coactivation compared to C-terminally truncated ATGL variants. The region is either directly involved in protein-protein interaction or essential for conformational changes required in the coactivation process. Three-dimensional models of the ATGL/CGI-58 complex with the artificial intelligence software AlphaFold demonstrated that a large surface area is involved in the protein-protein interaction. Mapping important amino acids for coactivation of both proteins, ATGL and CGI-58, onto the 3D model of the complex locates these essential amino acids at the predicted ATGL/CGI-58 interface thus strongly corroborating the significance of these residues in CGI-58-mediated coactivation of ATGL.

Authors

  • Natalia Kulminskaya
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Carlos Francisco Rodriguez Gamez
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Peter Hofer
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Ines Kathrin Cerk
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Noopur Dubey
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Roland Viertlmayr
    Institute of Molecular Biosciences, University of Graz, Graz, Austria.
  • Theo Sagmeister
    Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria.
  • Tea Pavkov-Keller
    Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria.
  • Rudolf Zechner
    Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria.
  • Monika Oberer
    Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria. Electronic address: m.oberer@uni-graz.at.

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