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  • Oxidative stress-responsive intracellular regulation specific for the angiostatic form of human tryptophanyl-tRNA synthetase.

Oxidative stress-responsive intracellular regulation specific for the angiostatic form of human tryptophanyl-tRNA synthetase.

Biochemistry (2005-01-05)
Keisuke Wakasugi, Tomomi Nakano, Isao Morishima
ABSTRACT

Tryptophanyl-tRNA synthetase (TrpRS) exists in two forms in human cells, i.e., a major form which represents the full-length protein and a truncated form (mini TrpRS) in which an NH(2)-terminal extension is deleted because of alternative splicing of its pre-mRNA. Mini TrpRS can act as an angiostatic factor, while full-length TrpRS is inactive. We herein show that an oxidized form of human glyceraldehyde-3-phosphate dehydrogenase (GapDH) interacts with both full-length and mini TrpRSs and specifically stimulates the aminoacylation potential of mini, but not full-length, TrpRS. In contrast, reduced GapDH did not bind to TrpRSs and did not influence their aminoacylation activity. Mutagenesis experiments clarified that the NH(2)-terminal Rossmann fold region of GapDH is crucial for its interaction with mini TrpRS as well as tRNA and for the regulation of its aminoacylation potential and suggested that monomeric GapDH can bind to mini TrpRS and stimulate its aminoacylation activity. These results suggest that the angiostatic human mini, but not the full-length, TrpRS may play an important role in the intracellular regulation of protein synthesis under conditions of oxidative stress.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Glyceraldehyde-3-phosphate Dehydrogenase from human erythrocytes, lyophilized powder, 50-150 units/mg protein
Sigma-Aldrich
Glyceraldehyde-3-phosphate Dehydrogenase from rabbit muscle, lyophilized powder, ≥75 units/mg protein
Supelco
GAPDH, standard for protein electrophoresis