A novel human homologue of the SH3BGR gene encodes a small protein similar to Glutaredoxin 1 of Escherichia coli.

Glutaredoxins (GRXs) are ubiquitous GSH-dependent oxidoreductases, which catalyze
the reduction of protein-glutathionyl-mixed disulfides and are considered to play
an important role in the enzymatic regulation of redox-sensitive proteins. In
this paper, we describe the identification and characterization of a new human
homologue of the SH3BGR gene, named SH3BGRL3 (SH3 domain 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 active site of GRX. This structural
feature raises the possibility that SH3BGRL3 could function as an endogenous
modulator of GRX biological activity. EGFP-SH3BGRL3 fusion protein expressed in
COS-7 cells localizes both to the nucleus and to the cytoplasm. The SH3BGRL3 gene
was mapped to chromosome 1p34.3-35.