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Pyroptosis
Pyroptosis is a highly inflammatory form of lytic programmed cell death that occurs most frequently upon infection with intracellular pathogens and is likely to form part of the antimicrobial response. This process promotes the rapid clearance of various bacterial, viral, fungal and protozoan infections by removing intracellular replication niches and enhancing the host's defensive responses. Pyroptosis can take place in immune cells and is also reported to occur in keratinocytes and some epithelial cells. The process is initiated by formation of a large supramolecular complex termed the inflammasome (also known as a pyroptosome) upon intracellular danger signals. The inflammasome activates a different set of caspases as compared to apoptosis, for example, caspase-1/4/5 in humans and caspase-11 in mice. These caspases contribute to the maturation and activation of several proinflammatory cytokines and pore-forming protein gasdermins. Formation of pores causes cell membrane ruptur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspases
Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cysteine protease activity – a cysteine in its active site nucleophilically attacks and cleaves a target protein only after an aspartic acid residue. As of 2009, there are 12 confirmed caspases in humans and 10 in mice, carrying out a variety of cellular functions. The role of these enzymes in programmed cell death was first identified in 1993, with their functions in apoptosis well characterised. This is a form of programmed cell death, occurring widely during development, and throughout life to maintain cell homeostasis. Activation of caspases ensures that the cellular components are degraded in a controlled manner, carrying out cell death with minimal effect on surrounding tissues. Caspases have other identified roles in programmed cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflammasome
Inflammasomes are cytosolic multiprotein oligomers of the innate immune system responsible for the activation of inflammatory responses. Activation and assembly of the inflammasome promotes proteolytic cleavage, maturation and secretion of pro-inflammatory cytokines interleukin 1β (IL-1β) and interleukin 18 (IL-18), as well as cleavage of Gasdermin-D. The N-terminal fragment resulting from this cleavage induces a pro-inflammatory form of programmed cell death distinct from apoptosis, referred to as pyroptosis, and is responsible for secretion of the mature cytokines, presumably through the formation of pores in the plasma membrane. Inflammasome activation is initiated by different kinds of cytosolic pattern recognition receptors (PRRs) that respond to either microbe-derived pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs) generated by the host cell. Pattern recognition receptors involved in inflammasomes comprise NLRs (nucleotide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSDMD
Gasdermin D (GSDMD) is a protein that in humans is encoded by the ''GSDMD'' gene on chromosome 8. It belongs to the gasdermin family which is conserved among vertebrates and comprises six members in humans, GSDMA, GSDMB, GSDMC, GSDMD, GSDME (DFNA5) and DFNB59 (Pejvakin). Members of the gasdermin family are expressed in a variety of cell types including epithelial cells and immune cells. GSDMA, GSDMB, GSDMC, GSDMD and GSDME have been suggested to act as tumour suppressors. Structure The structure of full-length GSDMD consists of two domains, the 31 kDa N-terminal (GSDMD-N) and 22 kDa C-terminal (GSDMD-C) domains, separated by a linker region. GSDMD-C can be divided into four subdomains and is composed of 10 α-helices and two β-strands, forming a compact globular fold. The linker helix contacts the two helix-repeats which consist of four-helix bundles. The middle domain comprises an antiparallel β-strand and a short α-helix. The first flexible loop of GSDMD-C, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caspase-1
Caspase-1/Interleukin-1 converting enzyme (ICE) is an evolutionarily conserved enzyme that proteolysis, proteolytically cleaves other proteins, such as the Protein precursor, precursors of the inflammatory cytokines Interleukin 1 beta, interleukin 1β and interleukin 18 as well as the pyroptosis inducer Gasdermin D, into active mature peptides. It plays a central role in cell immunity as an inflammatory response initiator. Once activated through formation of an inflammasome complex, it initiates a proinflammatory response through the cleavage and thus activation of the two inflammatory cytokines, Interleukin 1 beta, interleukin 1β (IL-1β) and interleukin 18 (IL-18) as well as pyroptosis, a programmed lytic cell death pathway, through cleavage of Gasdermin D. The two inflammatory cytokines activated by Caspase-1 are excreted from the cell to further induce the inflammatory response in neighboring cells. Cellular expression Caspase-1 is evolutionarily conserved in many eukaryot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmed Cell Death
Programmed cell death (PCD; sometimes referred to as cellular suicide) is the death of a cell (biology), cell as a result of events inside of a cell, such as apoptosis or autophagy. PCD is carried out in a biological process, which usually confers advantage during an organism's biological life cycle, lifecycle. For example, the Limb development, differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. PCD serves fundamental functions during both plant and animal tissue development. Apoptosis and autophagy are both forms of programmed cell death. Necrosis is the death of a cell caused by external factors such as trauma or infection and occurs in several different forms. Necrosis was long seen as a non-physiological process that occurs as a result of infection or injury, but in the 2000s, a form of programmed necrosis, called necroptosis, was recognized as an alternative form of pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
