Article

Phosphorylation of AfsR by multiple serine/threonine kinases in Streptomyces coelicolor A3(2).

Department of Biotechnology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan.
Gene (impact factor: 2.34). 07/2004; 334:53-61. DOI:10.1016/j.gene.2004.02.046
Source: PubMed

ABSTRACT AfsK, a protein serine/threonine kinase, autophosphorylates on serine and threonine residues and phosphorylates serine and threonine residues of AfsR, a transcriptional activator for afsS involved in secondary metabolism in Streptomyces coelicolor A3(2). pkaG encoding a 592-amino-acid protein and SCD10.09 (named afsL) encoding a 580-amino-acid protein, both of which encode an AfsK-like protein, were transcribed throughout growth. PkaG with a histidine-tag and the kinase catalytic domain of PkaG, produced in Escherichia coli, autophosphorylated dominantly on threonine and slightly on serine residues. In addition, these proteins phosphorylated AfsR on threonine and serine residues. The catalytic domain of AfsL also autophosphorylated and phosphorylated AfsR, on threonine and serine residues in both cases. AfsR was thus found to be phosphorylated by multiple kinases. Disruption of the chromosomal pkaG gene resulted in slightly reduced production of the pigmented antibiotic actinorhodin. These findings, together with the presence of about 40 AfsK homologues and at least five AfsR homologues in S. coelicolor A3(2), suggest that the regulatory networks via eukaryotic-type protein phosphorylation are more diverse and versatile than we have expected.

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Keywords

40 AfsK homologues
 
580-amino-acid protein
 
592-amino-acid protein
 
AfsK-like protein
 
catalytic domain
 
chromosomal pkaG gene
 
Escherichia coli
 
eukaryotic-type protein phosphorylation
 
five AfsR homologues
 
kinase catalytic domain
 
multiple kinases
 
phosphorylated AfsR
 
phosphorylates serine
 
pigmented antibiotic actinorhodin
 
protein serine/threonine kinase
 
proteins phosphorylated AfsR
 
regulatory networks
 
secondary metabolism
 
Streptomyces coelicolor A3(2)
 
transcriptional activator
 

Reiko Sawai