Protein-L-Isoaspartyl Methyltransferase (PIMT) Is Required for Survival ofSalmonellaTyphimurium at 42°C and Contributes to the Virulence in Poultry.
Poultry birds are asymptomatic reservoir ofSalmonellaTyphimurium (S. Typhimurium) but act as source of human infection for this bacterium. Inside the poultry,S. Typhimurium experiences several stresses, 42°C body temperature of birds is one of them. Proteins are highly susceptible to temperature mediated damage. Conversion of protein bound aspartate (Asp) residues to iso-aspartate (iso-Asp) is one of such modifications that occur at elevated temperature. Iso-Asp formation has been linked to protein inactivation and compromised cellular survival. Protein-L-isoaspartyl methyltransferase (PIMT) can repair iso-Asp back to Asp, thus enhances the cellular survival at elevated temperature. Here, we show that thepimtgene deletion strain ofS. Typhimurium (Δpimtmutant strain) is hypersensitive to 42°Cin vitro. The hypersusceptibility of Δpimtstrain is partially reversed by plasmid based complementation (trans-complementation) of Δpimtstrain. Following oral inoculation, Δpimtstrain showed defective colonization in poultry caecum, and compromised dissemination to spleen and liver. Interestingly, we have observed three and half folds induction of the PIMT protein following exposure ofS. Typhimurium to 42°C. Our data suggest a novel role ofpimtgene in the survival ofS. Typhimurium at elevated temperature and virulence.
Division of Veterinary Public Health, Indian Veterinary Research Institute Izatnagar, India.
Pavan K
PK
Pesingi
Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India.
Manoj
M
Kumawat
Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India.
Pranatee
P
Behera
Division of Immunology, Indian Veterinary Research Institute Izatnagar, India.
Sunil K
SK
Dixit
Division of Bacteriology and Mycology, Indian Veterinary Research Institute Izatnagar, India.
Rajesh K
RK
Agarwal
Division of Immunology, Indian Veterinary Research Institute Izatnagar, India.
Tapas K
TK
Goswami
Division of Biochemistry, Indian Veterinary Research Institute Izatnagar, India.
Manish
M
Mahawar
42°C; PIMT; Salmonella; isoaspartate; poultry