CaspaseKaskade

CaspaseKaskade refers to the programmed cell death pathway also known as apoptosis. This cascade of enzyme activation is fundamental to the development and maintenance of multicellular organisms. The process begins with the activation of initiator caspases, which then cleave and activate executioner caspases. These executioner caspases are the primary effectors of apoptosis, dismantling cellular components in a controlled manner.

There are two main pathways leading to caspase activation: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is triggered by internal cellular damage or stress, such as DNA damage or growth factor withdrawal. This leads to the release of cytochrome c from mitochondria, which then forms an apoptosome complex with Apaf-1 and caspase-9, activating caspase-9. The extrinsic pathway is initiated by external signals, such as the binding of death ligands to death receptors on the cell surface. This receptor activation recruits adapter proteins and initiator caspases, such as caspase-8, leading to their auto-activation.

Once activated, executioner caspases, primarily caspase-3, caspase-6, and caspase-7, systematically degrade essential cellular proteins. This includes proteins involved in DNA repair, cytoskeletal structure, and nuclear lamina. The controlled degradation results in characteristic morphological changes of apoptosis, such as cell shrinkage, chromatin condensation, and the formation of apoptotic bodies, which are then cleared by phagocytic cells. Dysregulation of the caspase cascade can contribute to various diseases, including cancer and neurodegenerative disorders.