title: Functional Analysis of GLRX5 Mutants Reveals Distinct Functionalities of GLRX5 Protein.
abstract: Glutaredoxin 5 (GLRX5) is a 156 amino acid mitochondrial protein that plays an essential role in mitochondrial iron-sulfur cluster transfer. Mutations in this protein were reported to result in sideroblastic anemia and variant nonketotic hyperglycinemia in human. Recently, we have characterized a Chinese congenital sideroblastic anemia patient who has two compound heterozygous missense mutations (c. 301 A>C and c. 443 T>C) in his GLRX5 gene. Herein, we developed a GLRX5 knockout K562 cell line and studied the biochemical functions of the identified pathogenic mutations and other conserved amino acids with predicted essential functions. We observed that the K101Q mutation (due to c. 301 A>C mutation) may prevent the binding of [Fe-S] to GLRX5 protein, while L148S (due to c. 443 T>C mutation) may interfere with [Fe-S] transfer from GLRX5 to iron regulatory protein 1 (IRP1), mitochondrial aconitase (m-aconitase) and ferrochelatase. We also demonstrated that L148S is functionally complementary to the K51del mutant with respect to Fe/S-ferrochelatase, Fe/S-IRP1, Fe/S-succinate dehydrogenase, and Fe/S-m-aconitase biosynthesis and lipoylation of pyruvate dehydrogenase complex and α-ketoglutarate dehydrogenase complex. Furthermore, we demonstrated that the mutations of highly conserved amino acid residues in GLRX5 protein can have different effects on downstream Fe/S proteins. Collectively, our current work demonstrates that GLRX5 protein is multifunctional in [Fe-S] protein synthesis and maturation and defects of the different amino acids of the protein will lead to distinct effects on downstream Fe/S biosynthesis.
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, No.11 Zhongguancun Beiyitiao, Beijing, 100190, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, No.11 Zhongguancun Beiyitiao, Beijing, 100190, China.|Laboratory of Molecular Iron Metabolism, College of Life Science, Hebei Normal University, Shijiazhuang, 050024, Hebei Province, China.
authors.forename: Yongwei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Anderson
authors.affiliation: Vita-Salute University, and IRCCS San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Camaschella
authors.affiliation: Laboratory of Molecular Iron Metabolism, College of Life Science, Hebei Normal University, Shijiazhuang, 050024, Hebei Province, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Chang
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, No.11 Zhongguancun Beiyitiao, Beijing, 100190, China.
authors.forename: Guangjun
authors.initials: G
authors.lastname: Nie
mesh_terms: D002460:Cell Line; D054477:Glutaredoxins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding
chemical_list: D054477:Glutaredoxins; D007506:Iron-Sulfur Proteins
keywords: GLRX5; IRON-SULFUR CLUSTER BIOSYNTHESIS; MUTATIONS