pseudocaspases

Pseudocaspases are a family of cysteine proteases that share structural similarities with caspases, a well-known group of proteases involved in programmed cell death. However, pseudocaspases are distinct from caspases in their substrate specificity and their role in cellular processes. They are characterized by the presence of a catalytic dyad composed of a cysteine and a histidine residue, similar to caspases. Unlike canonical caspases, which typically cleave after aspartate residues, pseudocaspases often cleave after specific arginine residues.

The known functions of pseudocaspases are diverse and continue to be an active area of research. Some pseudocaspases have been implicated in processes such as nutrient sensing, cell growth regulation, and stress responses. For instance, certain pseudocaspases have been shown to play a role in the response to nutrient deprivation, influencing metabolic pathways. Others are involved in the regulation of cell cycle progression. Their involvement in programmed cell death is also being investigated, though it appears to be distinct from the classical apoptotic pathways mediated by caspases.

Pseudocaspases are found in a wide range of organisms, including bacteria, archaea, and eukaryotes. Their evolutionary history suggests a divergence from the caspase lineage early in evolution. The precise molecular mechanisms by which pseudocaspases exert their functions are still being elucidated, but it is understood that their proteolytic activity is key to their biological roles. Understanding pseudocaspase function is important for gaining insights into fundamental cellular processes and potentially for developing new therapeutic strategies.