Requirements for the different cysteines in the chemotactic and desensitizing activity of human thioredoxin.
Thioredoxin (Trx) is a protein disulfide oxidoreductase that can be secreted and act as a chemoattractant for leukocytes. Like chemokines, it causes desensitization of monocytes against its chemotactic activity and that of monocyte chemoattractant protein-1 (MCP-1). To investigate the role of the redox properties of Trx, and particularly of some of its five cysteines, in its chemotactic and desensitizing action, we tested different mutants, including Trx80, a truncated form, and various mutants lacking specific cysteines: Trx C62S/C73S and the redox-inactive mutant Trx C32S/C35S. Of the mutants, only Trx80 maintained the chemotactic activity of wild-type Trx toward both monocytes and polymorphonuclear neutrophils, all of them desensitized monocytes against wild-type Trx or MCP-1, but not chemotactic peptide formyl-methionyl-leucil peptide. These data indicate that different redox-active cysteines are important for Trx chemotactic action, whereas its desensitizing action does not have these requirements, suggesting a redox-independent mechanism.
Bizzarri
Cinzia
C
Dompe' Research Center and Consorzio Biolaq, L'Aquila, Italy.
Holmgren
Arne
A
Pekkari
Klas
K
Chang
Geng
G
Colotta
Francesco
F
Ghezzi
Pietro
P
Bertini
Riccardo
R
D002465:Cell Movement; D018932:Chemokine CCL2 / Q000378:metabolism; D018925:Chemokines / Q000378:metabolism; D002633:Chemotaxis; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D009154:Mutation; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000378:metabolism; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013879:Thioredoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D018932:Chemokine CCL2; D018925:Chemokines; D010455:Peptides; D011994:Recombinant Proteins; D013879:Thioredoxins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D003545:Cysteine