Identification of residues crucial for the interaction between human neuroglobin and the α-subunit of heterotrimeric Gi protein.
Mammalian neuroglobin (Ngb) protects neuronal cells under conditions of oxidative stress. We previously showed that human Ngb acts as a guanine nucleotide dissociation inhibitor (GDI) for the α-subunits of heterotrimeric Gi/o proteins and inhibits the decrease in cAMP concentration, leading to protection against cell death. In the present study, we used an eukaryotic expression vector driving high-level expression of human wild-type Ngb or Ngb mutants that either exhibit or lack GDI activities in human cells. We demonstrate that the GDI activity of human Ngb is tightly correlated with its neuroprotective activity. We further demonstrate that Glu53, Glu60, and Glu118 of human Ngb are crucial for both the neuroprotective activity and interaction with Gαi1. Moreover, we show that Lys46, Lys70, Arg208, Lys209, and Lys210 residues of Gαi1 are important for binding to human Ngb. We propose a molecular docking model of the complex between human Ngb and Gαi1.
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Nozomu
N
Takahashi
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Keisuke
K
Wakasugi
D002460:Cell Line; D044385:GTP-Binding Protein alpha Subunits / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D005914:Globins / Q000235:genetics / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D062105:Molecular Docking Simulation; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D000078787:Neuroglobin; D011485:Protein Binding; D025941:Protein Interaction Mapping; D060066:Protein Interaction Maps
D044385:GTP-Binding Protein alpha Subunits; D020730:Guanine Nucleotide Dissociation Inhibitors; D050505:Mutant Proteins; D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D005914:Globins