%0 Journal Article
%T The Salmonella typhi Cell Division Activator Protein StCAP Impacts Pathogenesis by Influencing Critical Molecular Events.
%A Singh K
%A Vashishtha S
%A Chakraborty A
%A Kumar A
%A Thakur S
%A Kundu B
%J ACS Infect Dis
%V 10
%N 6
%D 2024 Jun 14
%M 38815059
%F 5.578
%R 10.1021/acsinfecdis.4c00001
%X Conserved molecular signatures in multidrug-resistant Salmonella typhi can serve as novel therapeutic targets for mitigation of infection. In this regard, we present the S. typhi cell division activator protein (StCAP) as a conserved target across S. typhi variants. From in silico and fluorimetric assessments, we found that StCAP is a DNA-binding protein. Replacement of the identified DNA-interacting residue Arg34 of StCAP with Ala34 showed a dramatic (15-fold) increase in Kd value compared to the wild type (Kd 546 nm) as well as a decrease in thermal stability (10 °C shift). Out of the two screened molecules against the DNA-binding pocket of StCAP, eltrombopag, and nilotinib, the former displayed better binding. Eltrombopag inhibited the stand-alone S. typhi culture with an IC50 of 38 μM. The effect was much more pronounced on THP-1-derived macrophages (T1Mac) infected with S. typhi where colony formation was severely hindered with IC50 reduced further to 10 μM. Apoptotic protease activating factor1 (Apaf1), a key molecule for intrinsic apoptosis, was identified as an StCAP-interacting partner by pull-down assay against T1Mac. Further, StCAP-transfected T1Mac showed a significant increase in LC3 II (autophagy marker) expression and downregulation of caspase 3 protein. From these experiments, we conclude that StCAP provides a crucial survival advantage to S. typhi during infection, thereby making it a potent alternative therapeutic target.