濡木研公開ラボセミナー

Glutathione Transferase-homology Domains as a Scaffold Protein in a Multicomponent Protein Complex

Beom Sik Kang博士(School of Life Sciences and Biotechnology, Kyungpook National University, Daegu, Republic of Korea)

2018年01月18日(Thu)    14:30-15:00  理学部3号館 326号室   

Glutathione transferase (GST) conjugates the sulfhydryl group of glutathione to xenobiotic substrates for detoxification and its homologs and isoforms have been described from bacteria to humans. Throughout evolution, GST-homology structures have spread into different proteins, including aminoacyl-tRNA synthetases (ARSs) and translational factors. Among human ARSs, GST homologs are found in methionyl-tRNA synthetase, valyl-tRNA synthetase, glutamylprolyl-tRNA synthetase, and cysteinyl-tRNA synthetase. Two ARS-interacting multifunctional proteins and two elongation factor 1B subunits also contain a GST domain. Although the functional implication of these embedded GST domains vary, they appear to play roles in protein assembly and folding. Since GST domains can form a dimer in two different ways using their two different binding interfaces, a GST domain can bind two GST domains simultaneously utilizing its both interfaces. Proteins carrying a GST domain can be assembled through their GST domains and we found tetrameric GST domain complexes in human multi-tRNA synthetase complex (MSC) and elongation factor 1B complex (eEF1B). In these complexes, the components containing a GST domain are assembled through their GST domains. Some proteins in MSC and eEF1B can further interact with other components to make a larger complex. Now we can consider the GST domain as a new member of a protein-interacting domain group and the GST complex as a novel scaffold protein.