Bacterial secreted effectors and caspase‐3 interactions

Abstract

Apoptosis is a critical process that intrinsically links organism survival to its ability to induce controlled death. Thus, functional apoptosis allows organisms to remove perceived threats to their survival by targeting those cells that it determines pose a direct risk. Central to this process are apoptotic caspases, enzymes that form a signalling cascade, converting danger signals via initiator caspases into activation of the executioner caspase, caspase-3. This enzyme begins disassembly of the cell by activating DNA degrading enzymes and degrading the cellular architecture. Interaction of pathogenic bacteria with caspases, and in particular, caspase-3, can therefore impact both host cell and bacterial survival. With roles outside cell death such as cell differentiation, control of signalling pathways and immunomodulation also being described for caspase-3, bacterial interactions with caspase-3 may be of far more significance in infection than previously recognized. In this review, we highlight the ways in which bacterial pathogens have evolved to subvert caspase-3 both through effector proteins that directly interact with the enzyme or by modulating pathways that influence its activation and activity.

Caspase-3 cleavage of Salmonella type III secreted effector protein SifA is required for localization of functional domains and bacterial dissemination

“…34 Caspase-3 activation during bacterial infection is also likely a common by-product of the coevolution of bacterial-host interactions, perhaps precipitated by the stress placed on host cells during invasion. [35][36][37][38][39] In addition to non-specific or indirect activation of caspase-3, bacterial effectors are also able to promote caspase-3 activation through subtle changes within cellular pathways or even through direct interaction with the enzyme. The outcome for the pathogenic intruder, such as S. Typhimurium is often an increase in infectivity rather than a clearing of the infection as expected by the conventional understanding of the protective role of apoptosis.…”

Expression of eukaryotic‐like protein in the microbiome of sponges

“…Cyanobacterial caspase homologs have been previously found to be associated with WD40 repeats (Asplund-Samuelsson 2015). Their function in prokaryotes is largely unexplored, and in the host-associated context, they might play a role in bacterial pathogenesis and host interaction by mimicking eukaryotic caspases and promoting cell survival (Wall & McCormick 2014). Sialidases have been considered virulence factors in many pathogenic organisms, which colonize mucosal surfaces by hydrolysing the protective barrier and facilitating bacterial adhesion (Corfield 1992;Wiggins et al 2001).…”

Caveolin-1 contributes to realgar nanoparticle therapy in human chronic myelogenous leukemia K562 cells

“…During apoptosis, pro-caspase-3 transforms to active enzyme when two cleaved monomers combine to form an active dimer. 40 Meanwhile, the balance between prosurvival Bcl2 and proapoptotic protein Bax is crucial for cell survival, and the ratio of Bcl2/Bax is becoming representative of cell apoptosis. 41 The present analysis of caspase-3 and Bcl2/Bax expression through Western blot showed that realgar NPs induced apoptosis in a dose-and time-dependent manner in K562 cells.…”