AppppA binds to several proteins in Escherichia coli, including the heat shock and oxidative stress proteins DnaK, GroEL, E89, C45 and C40.

AUTOR(ES)

Johnstone, D B

RESUMO

The dinucleotide AppppA (5',5'''-P1, P4-diadenosine tetraphosphate) is rapidly synthesized in cells exposed to heat stress or oxidative stress. Stress-induced AppppA accumulation has been observed in all cell types studied to date. In order to study the function(s) of AppppA, we created a mutation in the Escherichia coli gene that encodes the sole AppppN hydrolase (apaH). High levels of AppppA have subsequently been shown to affect many cellular processes, including expression of catabolite repressible genes and the ability to survive starvation, oxidative stress and near-UV irradiation. Nevertheless, the precise role of AppppA remains undefined. In order to better understand the mechanism by which AppppA exerts its effects, we attempted to determine which proteins bind to AppppA by synthesizing (alpha'-32P) 8-N3AppppA for use in photocrosslinking experiments with extract derived from cells with different genetic backgrounds and exposed to various stress conditions. We report here that several E. coli proteins bind AppppA, including the heat shock and oxidative stress proteins DnaK, GroEL, E89, C45 and C40. In addition, we show that apaH mutants, which have high basal levels of AppppA, are hypersensitive to killing by heat.

Documentos Relacionados

• Induction of heat shock proteins DnaK, GroEL, and GroES by salt stress in Lactococcus lactis.
• Induction of DnaK and GroEL heat shock proteins by fluoroquinolones in Escherichia coli.
• Increased synthesis of DnaK, GroEL, and GroES homologs by Francisella tularensis LVS in response to heat and hydrogen peroxide.
• AppppA, heat-shock stress, and cell oxidation.
• Transcriptional Analysis of the groES-groEL1, groEL2, and dnaK genes in Corynebacterium glutamicum: Characterization of Heat Shock-Induced Promoters