A novel human homologue of the SH3BGR gene encodes a small protein similarto glutaredoxin 1 of Escherichia coli

Glutaredoxins (GRXs) are ubiquitous GSH-dependent oxidoreductases, which ca talyze the reduction of protein-glutathionyl-mixed disulfides and are consi dered to play an important role in the enzymatic regulation of redox-sensit ive proteins. In this paper, we describe the identification and characteriz ation of a new human homologue of the SH3BGR gene, named SH3BGRL3 (SH3 doma in binding glutamic acid-rich protein like 3), SH3BGRL3 is widely expressed and codes for a highly conserved small protein, which shows a significant similarity to Glutaredoxin 1 (GRX1) of Escherichia coli and is predicted to belong to the Thioredoxin Superfamily, However, the SH3BGRL3 protein lacks both the conserved cysteine residues, which characterize the enzymatic act ive site of GRX, This structural feature raises the possibility that SH3BGR L3 could function as an endogenous modulator of GRX biological activity. EG FP-SH3BGRL3 fusion protein expressed in COS-7 cells localizes both to the n ucleus and to the cytoplasm, The SH3BGRL3 gene was mapped to chromosome 1p3 4.3-35. (C) 2001 Academic Press.