Immunochemical Identification of a Stat3 Analogue in Streptomycetes

Christopher J. Bakal¹, Dušica Vujaklija² and Julian Davies³*

¹Department of Medical Biophysics, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario, Canada, M5G 2M9
²Department for Molecular Genetics, Institute Ruđer Bošković, Bijenička 54, HR-10000 Zagreb, Croatia
³Department of Microbiology and Immunology, University of British Columbia, 300-6174 University Blvd., Vancouver, B.C., Canada, V6T 1Z3

Article history:
Received August 24, 2001
Accepted November 8, 2001

Key words:
Streptomyces, Jak-STAT, Stat3, tyrosine phosphorylation, prokaryotic signaling, antibody

Summary:
The STAT (signal transducers and activators of transcription) family of transcription factors are present in species as diverse as mammals, insects, plants and slime moulds. They play key roles in growth factor-regulated signaling pathways. Here we report the identification of a Stat-like protein in the prokaryote Streptomyces. Antibodies specific for mouse Stat3 cross-react with proteins in extracts of various Streptomyces sp. Furthermore, we demonstrate that, like eukaryotic Stat proteins, the Stat-like protein found in Streptomyces is phosphorylated on tyrosine. These results show that the Stats may play roles in cellular regulation in streptomycetes and suggest a bacterial evolution of these proteins.

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